ASMigrationDisplayItem showPicker Silent No-Op / Error 500 on iOS 26.x

I'm trying to explore accessory setup kit and migrate an existing CoreBluetooth-paired BLE device into AccessorySetupKit using ASMigrationDisplayItem. The regular ASPickerDisplayItem discovery picker works perfectly on the same device/session/Info.plist. But ASMigrationDisplayItem consistently fails.

Code

let descriptor = ASDiscoveryDescriptor()
descriptor.bluetoothServiceUUID = CBUUID(string: "0xFDEE")

let migrationItem = ASMigrationDisplayItem(
    name: "HUAWEI FreeClip 2",
    productImage: productImage,
    descriptor: descriptor
)
migrationItem.peripheralIdentifier = peripheralIdentifier
// peripheralIdentifier is a valid CBPeripheral.identifier UUID

// CBCentralManager is suspended before this call (suspendForASK)
session?.showPicker(for: [migrationItem]) { error in
    // Completion is either called with error 500, or NEVER called (silent no-op)
}

Test Results (8 rounds)

Round 6 logs (Error 500):

[ASK] Starting migration for peripheral: D0F13212-****
Picker already activated                              ← System message
[ASK] Migration picker failed: ASErrorDomain error 500.

Round 8 logs (Silent no-op, cleanest test):

XPC connection invalid                                ← System message
[ASK] Session invalidated: no error
[ASK] Session activated                               ← New session .activated
[ASK] Executing pending migration showPicker after .activated
// → NO pickerDidPresent, NO migrationComplete, NO completion callback, NO error, NO UI

Ruled Out

• Info.plist — regular ASPickerDisplayItem works with identical config
• Session state — .activated confirmed, session non-nil
• CBManager conflict — suspended before migration; round 3 ran before any CBManager existed
• User gesture — round 5 inside button tap handler (same context as working picker)
• Timing — delayed to viewDidAppear, waited for .activated event
• peripheralIdentifier — valid UUID, device is actively connected via CoreBluetooth

Questions

1. Is ASMigrationDisplayItem fully functional on iOS 26.x? Across 8 different invocation patterns, it either returns error 500 or silently no-ops — no UI ever appears.

2. What causes the residual "Picker already activated" state (error 500), and how do we properly reset it?

3. The XPC connection invalid system message appears consistently. Does this indicate the daemon is rejecting the migration request?

4. Are there prerequisites we're missing? E.g., must the device be disconnected from CB? Must NSBluetoothAlwaysUsageDescription be removed? Is there a different descriptor requirement for migration vs discovery?