SwiftUI: navigation bar shows title for first list item, otherwise shows “Back”

Question

I have basic list and detail views set up as shown below. The problem is that the first detail view shows "< Inbox" as the back button while the other rows show "< Back". I've tried various options and places for .navigationBarTitle but haven't found any way to solve this.

Main / list view:

    var body: some View {
        NavigationView {
            List {
                ForEach(userData.message) { messageSection in
                    Section(header: Text(messageSection.id)) {
                             ForEach(messageSection.messages) { message in
                                NavigationLink(destination: MessageDetail(message: message)) {
                                    MessageRow(message: message)
                                }
                             }
                     }
                 }
                }.navigationBarTitle(Text("Inbox"), displayMode: .inline)
        }
    }

Detail view:

    var body: some View {
        ScrollView {
            VStack {
...
            }
        }.navigationBarTitle(Text("\(self.message.title) (\(self.message.preview))"), displayMode: .inline)
    }

Answer 1

When the title is too long to display in the space allocated for the left bar button, the system uses "Back" as the button title instead.