I have come across this when putting a Button in the Navigation bar with an alert the "back" button disapear and get warning on loading last screen (with or without button) of

[Assert] displayModeButtonItem is internally managed and not exposed for DoubleColumn style. Returning an empty, disconnected UIBarButtonItem to fulfill the non-null contract.

This is a small code the replicates the problem.

Does anyone know want wrong and how to fix it.

struct ContentView: View {
    var body: some View {
        NavigationView {
            VStack {
                NavigationLink(destination: SecondView()) {
                        Text("Go To Second View")
                }
            }
            .navigationBarTitle("First View", displayMode: .inline)
        }
    }
}

struct SecondView: View {
    var body: some View {
        VStack {
            NavigationLink(destination: ThirdView()) {
                Text("Go to Third View")
            }
        }
        .navigationTitle("Second View")
    }
}

struct ThirdView: View {
    @State private var showingAlert = false

    var body: some View {
        VStack {
            Text("Last View")
        }
        .navigationTitle("Third View")
        .toolbar {
            Button {
                showingAlert.toggle()
            } label: {
                Label("Send Mail", systemImage: "tray.and.arrow.up.fill")
            }
        }
        .alert(isPresented: $showingAlert) {
            Alert(title: Text("Alert"), message: Text("alert message"), dismissButton: .default(Text("OK")))
        }
    }
}