Inconsistent button image scaling between dynamic type sizes '*** Large' and 'AX 1'

[Also submitted as FB20262774. Posting here in hopes of saving someone else from burning half a day chasing this down.]

Dynamic scaling of an Image() in a Button(), incorrectly decreases when transitioning from *** Large to AX 1 accessibility text sizes, instead of continuing to grow as expected. This occurs both on device and in the simulator, in iOS 18.6 and iOS 26.

Repro Steps

1. Create a project with sample code below
2. Show the preview if not showing
3. In Xcode Preview, click Canvas Device Settings and change Dynamic Type from *** Large to AX 1

Sample Code

struct ContentView: View {
    var body: some View {
        VStack(spacing: 30) {
            Text("Button Image Scaling Issue")
                .font(.system(size: 24, weight: .semibold))
            Text("Switch dynamic type from ***** Large** to **AX 1**. The **Button** icon shrinks while the **No Button** icon grows.")
                .font(.system(size: 14, weight: .regular))

            TestView(title: "No Button", isButton: false)
            TestView(title: "Button", isButton: true)
        }
        .padding()
    }
}

struct TestView: View {
    let title: String
    let isButton: Bool
    
    var body: some View {
        VStack {
            Text(title)
                .font(.system(size: 16))
                .foregroundColor(.secondary)
            
            if isButton {
                Button {} label: {
                    Image(systemName: "divide")
                        .font(.system(.largeTitle))
                }
                .buttonStyle(.bordered)
                .frame(height: 50)
            } else {
                Image(systemName: "divide")
                    .font(.system(.largeTitle))
                    .foregroundColor(.blue)
                    .frame(height: 50)
                    .background(Color.gray.opacity(0.2))
            }
        }
    }
}

Expected Result

Both the button and non-button images should continue to scale up proportionally when moving to larger accessibility text sizes.

Actual Result

When going from *** Large to AX 1…

• Non-button image gets larger ✅
• Button image gets smaller ❌

Screen Recording

System Info

Xcode Version 26.0 (17A321) iOS 26.0 and 18.6