Fade transitions cause grey flash with shadowed elements

[psx2]

When using any fade transition (.fade(), .fade(.cross), etc.) on a NavigationStack that contains NavigationLinks with shadowed elements, there's a noticeable grey flash during the transition. This only occurs when the shadowed elements have a white background.

Environment

• iOS 18.5
• SwiftUI
• swiftui-navigation-transitions 0.15.1
• Xcode 16.2

Reproduction Steps

1. Create cards with white background and shadows:
   .background(Color.white)
   .cornerRadius(20)
   .shadow(color: Color.black.opacity(0.15), radius: 0.5, x: 1, y: 1.5)
   .shadow(color: Color.black.opacity(0.25), radius: 1, x: 0, y: 0)

2. Apply fade transition to NavigationStack containing these cards:
   NavigationStack {
   // content with NavigationLinks containing shadowed cards
   } .navigationTransition(.fade(.cross)) // or .fade(), etc.

3. Tap on a card to navigate - observe a brief grey flash appears during the transition, specifically where shadows are rendered on white background.

[psx2]

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2025-08-29.at.12.17.22.mp4

[psx2]

This is not inherit to the package, but rather now Swift UI renders shadows!