We're experiencing an EXC_BAD_ACCESS (SIGSEGV) crash in UIView.drawHierarchy(in:afterScreenUpdates: false) that occurs only on iOS 26.3.1 and later. It does not reproduce on iOS 26.3.0 or earlier. Crash Stack Thread 0 (Main Thread) — EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0 libvDSP.dylib vConvert_XRGB2101010ToARGB8888_vec 1 ImageIO IIOIOSurfaceWrapper_CIF10::CopyImageBlockSetWithOptions 2 ImageIO IIOImageProviderInfo::CopyImageBlockSetWithOptions 3 ImageIO CGImageReadGetBytesAtOffset 4 CoreGraphics CGAccessSessionGetBytes 5 CoreGraphics img_data_lock 6 CoreGraphics CGSImageDataLock 7 CoreGraphics ripc_AcquireImage 8 CoreGraphics ripc_DrawImage 9 CoreGraphics CGContextDrawImage 10 UIKitCore -[UIView(Rendering) drawHierarchy:afterScreenUpdates:] The crash occurs during 10-bit CIF10 → 8-bit ARGB8888 pixel conversion when the IOSurface backing a UIImageView in the view hierarchy is deallocated mid-render. How to Reproduce Display a scrollable list with multiple UIImageViews loaded via an async image library Call drawHierarchy(in: bounds, afterScreenUpdates: false) on visible cells periodically Scroll to trigger image recycling Crash occurs sporadically — more likely under memory pressure or rapid image recycling What We've Tried Both UIKit off-screen rendering approaches crash on iOS 26.3.1: Approach Result drawHierarchy(afterScreenUpdates: false) EXC_BAD_ACCESS in CIF10 IOSurface decompression view.layer.render(in:) EXC_BAD_ACCESS in Metal (agxaAssertBufferIsValid) iOS Version Correlation iOS 26.3.0 and earlier: No crash iOS 26.3.1 (23D8133)+: Crash occurs (~5 events per 7 days) We suspect the ImageIO security patches in iOS 26.3 (CVE-2026-20675, CVE-2026-20634) may have changed IOSurface lifecycle timing, exposing a race condition between drawHierarchy's composited buffer read and asynchronous IOSurface reclamation by the OS. Crash Data We sampled 3 crash events: Event 1 (iOS 26.3.1): 71 MB free memory — memory pressure Event 2 (iOS 26.3.1): 88 MB free memory — memory pressure Event 3 (iOS 26.3.2): 768 MB free memory — NOT memory pressure Event 3 shows this isn't purely a low-memory issue. The IOSurface can be reclaimed even with ample free memory, likely due to async image recycling. Question Is this a known regression in iOS 26.3.1? Is there a safe way to snapshot a view hierarchy containing IOSurface-backed images without risking EXC_BAD_ACCESS? Should drawHierarchy gracefully handle the case where an IOSurface backing store is reclaimed during the render? Any guidance or workarounds would be appreciated. We've also filed this as Feedback (will update with FB number after submission).

I have (had) a view controller that does a bit of manual layout in a -viewDidLayout override. This was pretty easy to manage - however since introducing NSGlassEffectView into the view hierarchy I sometimes am getting hit with "Unable to simultaneously satisfy constraints" and Appkit would break a constraint to 'recover.' It appears translatesAutoresizingMaskIntoConstraints is creating some really weird fixed width and height constraints. Here I wasn't doing any autolayout - just add the glass view and set its frame in -viewDidLayout. At runtime since I do manual layout in -viewDidLayout the frames are fixed and there is no real "error" in my app in practice though I wanted to get rid of the constraint breaking warning being logged because I know Autolayout can be aggressive about 'correctness' who knows if they decide to throw and not catch in the future. In my perfect world I would probably just prefer a view.doesManualLayout = YES here - the subviews are big containers no labels so localization is not an issue for me. Rather than playing with autoresizing masks to get better translated constraints I decided to set translatesAutoresizingMaskIntoConstraints to NO and make the constraints myself. Now I get hit with the following exception: "The window has been marked as needing another Layout Window pass, but it has already had more Layout Window passes than there are views in the window" So this happens because the view which now has constraints -- I adjusted the frame of it one point in -viewDidLayout. My question is - is not legal to make changes in -viewDidLayout - which seems like the AppKit version of -viewDidLayoutSubviews. In UIKit I always thought it was fine to make changes in -viewDidLayoutSubviews to frames - even if constraints were used - this is a place where you could override things in complex layouts that cannot be easily described in constraints. But in AppKit if you touch certain frames in -viewDidLayout it can now cause this exception (also related: https://developer.apple.com/forums/thread/806471) I will change the constant of one of the constraints to account for the 1 point adjustment but my question still stands - is it not legal to touch frames in -viewDidLayout when autolayout constraints are used on that subview? It is (or at least was if I remember correctly) permitted to change the layout in -viewDidLayoutSubviews in UIKit but AppKit seems to be more aggressive in its checking for layout correctness). What about calling -sizeToFit on a control in viewDidLayout or some method that has side effect of invalidating layout in a non obvious way, is doing things like this now 'dangerous?' Shouldn't AppKit just block the layout from being invalidated from within -viewDidLayout - and leave whatever the layout is as is when viewDidLayout returns (thus making -viewDidLayout a useful place to override layout in the rare cases where you need a sledgehammer?)

I have a collection view that covers all the screen and it is scrolling behavior is paging. This collection view is embedded in a UIViewRepresentable and used in a SwiftUI app. The issue is that when users rotate the devices, sometimes the CollectionView.contentOffset get miscalculated and shows 2 pages. This is the code that I'm using for the collectionView and collectionViewLayout: class PageFlowLayout: UICollectionViewFlowLayout { override class var layoutAttributesClass: AnyClass { UICollectionViewLayoutAttributes.self } private var calculatedAttributes: [UICollectionViewLayoutAttributes] = [] private var calculatedContentWidth: CGFloat = 0 private var calculatedContentHeight: CGFloat = 0 public weak var delegate: PageFlowLayoutDelegate? override var collectionViewContentSize: CGSize { return CGSize(width: self.calculatedContentWidth, height: self.calculatedContentHeight) } override init() { super.init() self.estimatedItemSize = .zero self.scrollDirection = .horizontal self.minimumLineSpacing = 0 self.minimumInteritemSpacing = 0 self.sectionInset = .zero } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } override func prepare() { guard let collectionView = collectionView, collectionView.numberOfSections > 0, calculatedAttributes.isEmpty else { return } estimatedItemSize = collectionView.bounds.size for item in 0..<collectionView.numberOfItems(inSection: 0) { let indexPath = IndexPath(item: item, section: 0) let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath) let itemOrigin = CGPoint(x: CGFloat(item) * collectionView.frame.width, y: 0) attributes.frame = .init(origin: itemOrigin, size: collectionView.frame.size) calculatedAttributes.append(attributes) } calculatedContentWidth = collectionView.bounds.width * CGFloat(calculatedAttributes.count) calculatedContentHeight = collectionView.bounds.size.height } override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? { return calculatedAttributes.compactMap { return $0.frame.intersects(rect) ? $0 : nil } } override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? { return calculatedAttributes[indexPath.item] } override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool { guard let collectionView else { return false } if newBounds.size != collectionView.bounds.size { return true } if newBounds.size.width > 0 { let pages = calculatedContentWidth / newBounds.size.width // If the contentWidth matches the number of pages, // if not it requires to layout the cells let arePagesExact = pages.truncatingRemainder(dividingBy: 1) == 0 return !arePagesExact } return false } override func invalidateLayout() { calculatedAttributes = [] super.invalidateLayout() } override func shouldInvalidateLayout(forPreferredLayoutAttributes preferredAttributes: UICollectionViewLayoutAttributes, withOriginalAttributes originalAttributes: UICollectionViewLayoutAttributes) -> Bool { guard let collectionView, #available(iOS 18.0, *) else { return false } return preferredAttributes.size != collectionView.bounds.size } override func invalidateLayout(with context: UICollectionViewLayoutInvalidationContext) { guard let customContext = context as? UICollectionViewFlowLayoutInvalidationContext else { return } if let collectionView, let currentPage = delegate?.currentPage() { let delta = (CGFloat(currentPage) * collectionView.bounds.width) - collectionView.contentOffset.x customContext.contentOffsetAdjustment.x += delta } calculatedAttributes = [] super.invalidateLayout(with: customContext) } override func prepare(forAnimatedBoundsChange oldBounds: CGRect) { super.prepare(forAnimatedBoundsChange: oldBounds) guard let collectionView else { return } if oldBounds.width != collectionView.bounds.width { invalidateLayout() } } override func targetContentOffset(forProposedContentOffset proposedContentOffset: CGPoint) -> CGPoint { guard let collectionView, let currentPage = delegate?.currentPage() else { return .zero } let targetContentOffset = super.targetContentOffset(forProposedContentOffset: proposedContentOffset) let targetPage = targetContentOffset.x / collectionView.frame.width if targetPage != CGFloat(currentPage) { let xPosition = CGFloat(currentPage) * collectionView.frame.width return CGPoint(x: xPosition, y: 0) } return targetContentOffset } // This function updates the contentOffset in case is wrong override func finalizeCollectionViewUpdates() { guard let collectionView, let currentPage = delegate?.currentPage() else { return } let xPosition = CGFloat(currentPage) * collectionView.bounds.width if xPosition != collectionView.contentOffset.x { let offset = CGPoint(x: xPosition, y: 0) collectionView.setContentOffset(offset, animated: false) } } } The full implementation is attached in the .txt file: RotationTestView.txt

When tapping the currently selected time in a TimePicker (wheel style) component to invoke the inline numeric pad popover, the popover renders incorrectly on iPadOS 26.4.1 — it appears as a very narrow single-line/bar rather than the full numeric keypad layout. Steps to Reproduce: Run Reminder, create a new reminder and add a custom time Tap the currently selected time value to trigger the numeric pad popover Observe the popover layout Expected Result: A properly sized popover appears containing a full numeric keypad, allowing direct numeric input of the time value — consistent with behavior on iPadOS 18.x Actual Result: The popover appears as an extremely narrow horizontal bar (single line height), making the numeric pad unusable Regression: Works correctly on iPadOS 18.x through iPadOS 26.3. Broken on iPadOS 26.4.1 (Xcode 26.x simulator and/or physical device). https://www.youtube.com/shorts/bd3pYA3B-iI https://www.youtube.com/shorts/wSHzepHBwEY Feedback: FB22517457

I am facing weird keyboard issue when building the app with Xcode 26 recently. Actual behaviour I need is: But one below is the issue as the keyboard keys are greyed out: Please tell how to resolve this issue

I am currently migrating an app from the classic UITableViewDataSource to UITableViewDiffableDataSource. In certain complex cases, I find myself needing to toggle between the UITableViewDataSource and UITableViewDiffableDataSource on a single UITableView instance. Apple's official documentation for UITableViewDiffableDataSource contains a strict warning: "Do not change the dataSource on the table view after you configure it with a diffable data source. If the table view needs a new data source after you configure it initially, create and configure a new table view and diffable data source." I’m seeking clarification on: Internal State: What specific UIKit caching or internal state is corrupted if we nil out the diffable source and re-assign a classic one? Background Processes: Does the background diffing engine pose a risk (race conditions/crashes) if the source is swapped while a diff is calculating? The "Safe" Reset: If swapping is truly necessary, is there a verified cleanup sequence (e.g., clearing snapshots first) that avoids the need to recreate the UITableView entirely?

Hi, I'm using a TabView and for a given case I wish to have the icon of the Tab animated by symbolEffect to signify a state. The symbolEffect however doesn't seem to have an effect when used on a tab's label image. Is it really not possible? Tab(value: .hello) { EmptyView() } label: { Image(systemName: "hand.wave.fill") .symbolEffect(.wiggle, options: .repeating) } I still wish to use the TabView because it's amazing.

This example application crashes when entering any text to the token field with FAULT: NSGenericException: The window has been marked as needing another Update Constraints in Window pass, but it has already had more Update Constraints in Window passes than there are views in the window. The app uses controlTextDidChange to update a live preview where it accesses the objectValue of the token field. If one character is entered, it also looks like the NSTokenFieldDelegate methods tokenField(_:styleForRepresentedObject:) tokenField(_:editingStringForRepresentedObject:) tokenField(_:representedObjectForEditing:) are called more than 10000 times until the example app crashes on macOS Tahoe 26 beta 6. I've reported this issue with beta 1 as FB18088608, but haven't heard back so far. I have multiple occurrences of this issue in my app, which is working fine on previous versions of macOS. I haven't found a workaround yet, and I’m getting anxious of this issue persisting into the official release.

I have a question regarding cold start and pre-warming behavior on iOS. I’m developing a SwiftUI app that continuously receives data from a BLE device in the background. We’ve observed that after the BLE stream stops, the OS often terminates our app. Later, when the sensor comes back into range, iOS appears to relaunch (or reinitialize) the app. In our app, we use a WindowGroup like this: WindowGroup { AppView(store: store) } We’ve placed our BLE reconnection logic inside a .task modifier in AppView. What’s confusing is this: Most of the time, when the app is relaunched, AppView is created and the .task runs as expected. However, in about 1 out of 10 cases, AppView is not created at all, so the .task does not execute. I’m trying to understand: Under what conditions does iOS relaunch an app without fully initializing the SwiftUI view hierarchy? Is this related to pre-warming or background relaunch mechanisms (e.g., CoreBluetooth state restoration)? What determines whether the WindowGroup and root view are actually instantiated? Any insight into the system’s relaunch behavior or lifecycle in this scenario would be greatly appreciated.

When I create a SwiftUI toolbar item with placement of .keyboard on iOS 26, the item appears directly on top of and in contact with the keyboard. This does not look good visually nor does it match the behavior seen in Apple's apps, such as Reminders. Adding padding to the contents of the toolbar item only expands the size of the item but does not separate the capsule background of the item from the keyboard. How can I add vertical padding or spacing to separate the toolbar item capsule from the keyboard?

Hello, I am encountering a UI layout issue on iOS 26 where UITabBar items become squashed or overlapping during device rotation (from Portrait to Landscape). This glitch occurs specifically when a custom UITabBarAppearance is applied. 1. "Liquid Glass" and UITabBar Customization According to TN3106, Apple states: "Starting in iOS 26, reduce your use of custom backgrounds in navigation elements and controls. While the techniques in this document remain valid for iOS 18 and earlier, prefer to remove custom effects and let the system determine the navigation bar background appearance. Any custom backgrounds and appearances you use in the navigation bar might overlay or interfere with Liquid Glass or other effects that the system provides, such as the scroll edge effect." Does this guidance also apply to UITabBar? Specifically, could setting a custom background color via UITabBarAppearance interfere with internal layout constraints required for the Liquid Glass effect to adapt correctly during orientation changes? It appears that the internal UIStackView may fail to recalculate width in time when these system effects are active. 2. Validation of the Layout Workaround To maintain our app's visual identity while resolving this squashing issue, I implemented the following fix within the transition coordinator of my UITabBarController: Code Implementation (Objective-C) [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> _Nonnull context) { // Forcing a layout refresh to synchronize with the rotation animation [weakSelf.tabBar invalidateIntrinsicContentSize]; [weakSelf.tabBar setNeedsLayout]; [weakSelf.tabBar layoutIfNeeded]; } completion:nil]; Is manually invalidating the intrinsic content size an acceptable practice for iOS 26? Or is there a more "system-native" approach to ensure UITabBar layout remains stable and compatible with Liquid Glass, especially when custom appearances are necessary?

I am an audio plugin developer. 11.2.1 we were able to drag audio from the arrange page into the plugin. 11.2.2. that is now broken. I saw someone have a similar post, but MIDI. Any help would be greatly appreciated.

Logic Pro recently changed the way it accepts drag and drop. If the ItemProvider contains UTType.midi, then Logic Pro shows visual feedback for the drop operation, but when the item is dropped, nothing happens. In the past, drag-and-drop used to work. With today's version (Logic Pro 11.2), the only way I was able to successfully drop MIDI was to provide UTType.fileURL and no other data types. But that's not a viable solution; I need other data types to be included too. As a side note, I tested with Ableton Live 12 and it works with no issue. Is this a bug in Logic Pro? What ItemProvider structure does Logic Pro expect to correctly receive the MIDI data?

Navigation title scroll along with the content in iOS 26. working fine in iOS 18 and below. One of my UI component is outside the scrollview which is causing the issue. var body: some View { VStack { Rectangle() .frame(maxWidth: .infinity) .frame(height: 60) .padding(.horizontal) .padding(.top) ScrollView { ForEach(0...5, id: \.self) { _ in RoundedRectangle(cornerRadius: 10) .fill(.green) .frame(maxWidth: .infinity) .frame(height: 100) .padding(.horizontal) } } } .navigationTitle("Hello World") } }

Fatal Exception: NSInternalInconsistencyException Cannot remove an observer <WKWebView 0x135137800> for the key path "configuration.enforcesChildRestrictions" from <STScreenTimeConfigurationObserver 0x13c6d7460>, most likely because the value for the key "configuration" has changed without an appropriate KVO notification being sent. Check the KVO-compliance of the STScreenTimeConfigurationObserver [class.] I noticed that on iOS 26, WKWebView registers STScreenTimeConfigurationObserver, Is this an iOS 26 system issue? What should I do?

Hello everyone, I’m running into an issue where a partial sheet repeatedly presents and dismisses in a loop. Setup The main screen is presented using fullScreenCover From that screen, a button triggers a standard partial-height sheet The sheet is presented using .sheet(item:) Expected Behavior Tapping the button should present the sheet once and allow it to be dismissed normally. Actual Behavior After the sheet is triggered, it continuously presents and dismisses. What I’ve Verified The bound item is not being reassigned in either the parent or the presented view There is no .task, .onAppear, or .onChange that sets the item again The loop appears to happen without any explicit state updates Additional Context I encountered a very similar issue when iOS 26.0 was first released At that time, moving the .sheet modifier to a higher parent level resolved the issue The problem has now returned on iOS 26.4 beta I’m currently unable to reproduce this in a minimal sample project, which makes it unclear whether: this is a framework regression, or I’m missing a new presentation requirement Environment iOS: 26.4 beta Xcode: 26.4 beta I’ve attached a screen recording of the behavior. Has anyone else experienced this with a fullScreenCover → sheet flow on iOS 26.4? Any guidance or confirmation would be greatly appreciated. Thank you!

In my CarPlaySceneDelegate.swift, I have two tabs: The first tab uses a CPListImageRowItem with a CPListImageRowItemRowElement. The scroll direction is inverted, and the side button does not function correctly. The second tab uses multiple CPListItem objects. There are no issues: scrolling works in the correct direction, and the side button behaves as expected. Steps To Reproduce Launch the app. Connect to CarPlay. In the first tab, scroll up and down, then use the side button to navigate. In the second tab, scroll up and down, then use the side button to navigate. As observed, the scrolling behavior is different between the two tabs. Code Example: import CarPlay import UIKit class CarPlaySceneDelegate: UIResponder, CPTemplateApplicationSceneDelegate { var interfaceController: CPInterfaceController? func templateApplicationScene( _ templateApplicationScene: CPTemplateApplicationScene, didConnect interfaceController: CPInterfaceController ) { self.interfaceController = interfaceController downloadImageAndSetupTemplates() } func templateApplicationScene( _ templateApplicationScene: CPTemplateApplicationScene, didDisconnectInterfaceController interfaceController: CPInterfaceController ) { self.interfaceController = nil } private func downloadImageAndSetupTemplates() { let urlString = "https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRcYUjd1FYkF04-8Vb7PKI1mGoF2quLPHKjvnR7V4ReZR8UjW-0NJ_kC7q13eISZGoTCLHaDPVbOthhH9QNq-YA0uuSUjfAoB3PPs1aXQ&s=10" guard let url = URL(string: urlString) else { setupTemplates(with: UIImage(systemName: "photo")!) return } URLSession.shared.dataTask(with: url) { [weak self] data, _, _ in let image: UIImage if let data = data, let downloaded = UIImage(data: data) { image = downloaded } else { image = UIImage(systemName: "photo")! } DispatchQueue.main.async { self?.setupTemplates(with: image) } }.resume() } private func setupTemplates(with image: UIImage) { // Tab 1 : un seul CPListImageRowItem avec 12 CPListImageRowItemRowElement let elements: [CPListImageRowItemRowElement] = (1...12).map { index in CPListImageRowItemRowElement(image: image, title: "test \(index)", subtitle: nil) } let rowItem = CPListImageRowItem(text: "Images", elements: elements, allowsMultipleLines: true) rowItem.listImageRowHandler = { item, elementIndex, completion in print("tapped element \(elementIndex)") completion() } let tab1Section = CPListSection(items: [rowItem]) let tab1Template = CPListTemplate(title: "CPListImageRowItemRowElement", sections: [tab1Section]) // Tab 2 : 12 CPListItem simples let tab2Items: [CPListItem] = (1...12).map { index in let item = CPListItem(text: "Item \(index)", detailText: "Detail \(index)") item.handler = { _, completion in print("handler Tab 2") completion() } return item } let tab2Section = CPListSection(items: tab2Items) let tab2Template = CPListTemplate(title: "CPListItem", sections: [tab2Section]) // CPTabBarTemplate avec les deux tabs let tabBar = CPTabBarTemplate(templates: [tab1Template, tab2Template]) interfaceController?.setRootTemplate(tabBar, animated: true) } } Here is a quick video:

I’ve been investigating a noticeable animation hitch when interactively dismissing a sheet over a SwiftUI screen with moderate complexity. This was not the case on iOS 18, so I’m curious if others are seeing the same on iOS 26 or have found any mitigations. When dismissing a sheet via the swipe gesture, there’s a visible hitch right after lift-off. The hitch comes from layout work in the underlying view (behind the sheet) The duration scales with the complexity of that view (e.g. number of TextFields/layout nodes) The animation for programmatic dismiss (e.g. tapping a “Done” button) is smooth, although it hangs for a similar amount of time before dismissing, so it appears that the underlying work still happens. SwiftUI is not reevaluating the body during this (validated with Self._printChanges()), so that is not the cause. Using Instruments, the hitch shows up as a layout spike on the main thread: 54ms UIView layoutSublayersOfLayer 54ms └─ _UIHostingView.layoutSubviews 38ms └─ SwiftUI.ViewGraph.updateOutputs 11ms ├─ partial apply for implicit closure #1 in closure #1 │ in closure #1 in Attribute.init<A>(_:) 4ms └─ -[UIView For the same hierarchy with varying complexity: ~3 TextFields in a List: ~25ms (not noticeable) ~20+ TextFields: ~60ms (clearly visible hitch) The same view hierarchy on iOS 18 did not exhibit a visible hitch. I’ve tested this on an iOS 26.4 device and simulator. I’ve also included a minimum reproducible example that illustrates this: struct ContentView: View { @State var showSheet = false var body: some View { NavigationStack { ScrollView { ForEach(0..<120) { _ in RowView() } } .navigationTitle("Repro") .toolbar { ToolbarItem(placement: .topBarTrailing) { Button("Present") { showSheet = true } } } .sheet(isPresented: $showSheet) { PresentedSheet() } } } } struct RowView: View { @State var first = "" @State var second = "" var body: some View { VStack(alignment: .leading, spacing: 12) { Text("Row") .font(.headline) HStack(spacing: 12) { TextField("First", text: $first) .textFieldStyle(.roundedBorder) TextField("Second", text: $second) .textFieldStyle(.roundedBorder) } HStack(spacing: 12) { Text("Third") Text("Fourth") Image(systemName: "chevron.right") } } } } struct PresentedSheet: View { @Environment(\.dismiss) private var dismiss var body: some View { NavigationStack { List {} .navigationTitle("Swipe To Dismiss Me") .toolbar { ToolbarItem(placement: .topBarTrailing) { Button("Done") { dismiss() } } } } } } Is anyone else experiencing this and have any mitigations been found beyond reducing view complexity? I’ve filed a feedback report under FB22501630.

in iOS26.4, after installing the app for the first time, opening the app and clicking on the UITextField input box will trigger the system to pop up the network permission application interface. This issue did not exist before iOS 26.3, only in iOS 26.4. This is a fatal bug where the network permission request box should not pop up when the developer has not called the network related API.

Environment: Xcode Version: Xcode 26.3 Affected iOS Versions: iOS 26.1 and later Working iOS Versions: iOS 26.0 and earlier Tested Devices: iPhone 15 Pro (iOS 26.2) - ❌ Bug presents iPhone 17 (iOS 26.1) - ❌ Bug presents iPhone Air (iOS 26.0) - ✅ Works as expected iPhone 16 Pro Max (iOS 18.0) - ✅ Works as expected Description: We have identified a severe localization regression regarding the setAlternateIconName(_:completionHandler:) API starting from iOS 26.1. Our application is strictly restricted to support only Traditional Chinese (zh-TW / zh-Hant). We have correctly configured CFBundleLocalizations, CFBundleDevelopmentRegion, and explicitly set CFBundleAllowMixedLocalizations to YES in our Info.plist. In iOS 26.0 and earlier, when changing the app icon, the system alert correctly displays in Traditional Chinese. However, in iOS 26.1 and later, the alert unexpectedly falls back to English, completely ignoring the app's localization constraints and the user's preferred device language. Crucial Observation: We noticed a significant behavioral change: in iOS 26.1+, invoking setAlternateIconName forces the app to enter the sceneWillResignActive state before the alert appears. This behavior did not exist prior to iOS 26.1. This strongly suggests that the alert has been moved to an out-of-process overlay managed by SpringBoard. It appears that the system cache is failing to properly resolve the app's CFBundleLocalizations during this out-of-process presentation. Steps to Reproduce: Create an iOS application restricted to Traditional Chinese (zh-TW). Set CFBundleDevelopmentRegion to zh-Hant in Info.plist. Set the CFBundleLocalizations array to contain only zh-TW (or zh-Hant). Set CFBundleAllowMixedLocalizations to YES. Implement setAlternateIconName to trigger the app icon change. Run the app on a device running iOS 26.1 or later (ensure the device's system language is set to Traditional Chinese). Trigger the icon change action. Expected Result: The app should NOT trigger sceneWillResignActive (maintaining iOS 26.0 behavior); OR the out-of-process system alert must correctly read the Info.plist and display the prompt in Traditional Chinese. Actual Result: The app immediately triggers sceneWillResignActive and loses focus. The system overlay alert appears but ignores all Traditional Chinese settings, displaying an English interface instead. Any insights or workarounds from the engineering team would be highly appreciated. We'd like to know if this is a known SpringBoard rendering issue in iOS 26.1+. Thank you!