List rows partially obscured by navigation bar briefly render fully opaque when switching tabs (iOS 26)

Overview

In iOS 26, a List embedded in a NavigationStack inside a TabView exhibits a visual glitch when switching tabs.

When the list is scrolled such that some rows are partially obscured by the navigation bar, the system correctly applies a fade/opacity effect to those rows. However, if the user switches to another tab while rows are in this partially obscured (faded) state, those rows briefly flash at full opacity during the tab transition before disappearing.

This flash is visually distracting and appears to be inconsistent with the intended scroll-edge opacity behavior.

• The issue occurs only for rows partially obscured by the navigation bar.
• Rows partially obscured by the tab bar do not exhibit this flashing behavior.

Steps to Reproduce:

1. Run the attached minimal reproduction on iOS 26.
2. Open the first tab.
3. Scroll the list so that some rows are partially hidden behind the navigation bar (showing the native faded appearance).
4. While rows are in this partially faded state, switch to the second tab.
5. Observe that the faded rows briefly render fully opaque during the tab switch.

Expected Behavior:

Rows that are partially obscured by the navigation bar should maintain consistent opacity behavior during tab transitions, without flashing to full opacity.

import SwiftUI

@main
struct NavBarReproApp: App {
    /// Minimal repro for iOS 26:
    /// - TabView with two tabs
    /// - First tab: NavigationStack + List
    /// - Scroll so some rows are partially behind the nav bar (faded)
    /// - Switch tabs: those partially-faded rows briefly flash fully opaque. Partially faded rows under the tab bar do not flash
    
    private let items = Array(0..<200).map { "Row \($0)" }
    
    var body: some Scene {
        WindowGroup {
            TabView {
                NavigationStack {
                    List {
                        ForEach(items, id: \.self) { item in
                            Text(item)
                        }
                    }
                    .navigationTitle("One")
                    .navigationBarTitleDisplayMode(.inline)
                }
                .tabItem { Label("One", systemImage: "1.circle") }

                NavigationStack {
                    Text("Second tab")
                        .navigationTitle("Two")
                        .navigationBarTitleDisplayMode(.inline)
                }
                .tabItem { Label("Two", systemImage: "2.circle") }
            }
        }
    }
}