Xcode 26.0 + iOS 26.0 の組み合わせで NavigationStack の Large Titleを表示させると、タイトルが背景色の裏に隠れてしまう不具合

ContentView.swift

//
//  ContentView.swift
//  SampleNavigationTitle
//
//  Created by wada.kenji on 2025/10/07.
//

import SwiftUI

struct ContentView: View {
    var body: some View {
        NavigationStack {
            List {
                ForEach(0 ..< 20) { index in
                    Text("Item \(index)")
                }
            }
            .navigationTitle(Text("タイトル"))
            .defaultNavigationBar()
        }
    }
}

struct CustomNavigationBarModifier: ViewModifier {
    init() {
        let appearance = UINavigationBarAppearance()
        appearance.configureWithOpaqueBackground()
        appearance.backgroundColor = .green
//        // タイトルが背景の裏側に存在している
//        appearance.backgroundColor = .green.withAlphaComponent(0.5)
        appearance.largeTitleTextAttributes = [
            .font: UIFont.systemFont(ofSize: 30, weight: .heavy),
            .foregroundColor: UIColor.black,
        ]
        appearance.titleTextAttributes = [
            .font: UIFont.systemFont(ofSize: 15, weight: .regular),
            .foregroundColor: UIColor.black,
        ]
        UINavigationBar.appearance().standardAppearance = appearance
        UINavigationBar.appearance().scrollEdgeAppearance = appearance
    }

    func body(content: Content) -> some View {
        ZStack { content }
    }
}

extension View {
    func defaultNavigationBar() -> some View {
        modifier(CustomNavigationBarModifier())
    }
}

#Preview {
    ContentView()
}