ChildMutateParentNavStackPushBug.swift

import SwiftUI

struct Child: View {
    @Binding var binding: Int

    var body: some View {
        VStack {
            Text("x = \(binding)")
            Button("Mutate parent view .x") {
                binding += 1    // this will cause a new child view push onto the nav stack
            }
        }
    }
}

struct ContentView: View {
    @State var x = 100

    var body: some View {
        NavigationView {
            VStack {
                Text("Hello, x = \(x)")
            }
            .navigationTitle(Text("Nav Stack Keep Pushing"))
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    NavigationLink(destination: Child(binding: $x)) {
                        // image interpolation here doesn't work
//                        Text("Child\(Image(systemName: "chevron.right"))")
                        // so have to use a HStack
                        HStack(spacing: 0) {
                            Text("Child")
                            Image(systemName: "chevron.right")                        }
                    }
                }
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Fixed in iOS 15b4!