SwiftUI toolbar disappears after navigation on iOS

Hello,

with the following setup the bottom toolbar on SubView disappears as soon as I navigate down to SubSubView and go back to SubView. I tested this behavior on different simulators and my own device iPhone 12pro with Xcode 12.5.

struct ContentView: View {
    var body: some View {
        NavigationView {
            NavigationLink(destination: SubView()) {
                Text("Go to sub view")
                    .font(.largeTitle)
            }
            .navigationTitle("Content")
        }
        .navigationViewStyle(StackNavigationViewStyle())
    }
}

struct SubView: View {
    var body: some View {
        List {
            NavigationLink(destination: SubSubView()) {
                Text("Go to sub sub view")
            }
        }
        .navigationTitle("Sub View")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .bottomBar) {
                Button(action: {}, label: {
                    Text("Action")
                })
            }
        }
    }
}

struct SubSubView: View {
    var body: some View {
        Text("end of way")
            .font(.largeTitle)
            .navigationTitle("Sub Sub View")
            .navigationBarTitleDisplayMode(.inline)
    }
}

Regards Pawel