SwiftUI / iOS: remove overlaying text in Navigation Bar

From time to time my SwiftUI app shows the following behavior in the Navigation Bar. Unfortunately I cannot reproduce it.
It is a tabview app with each tab being a NavigationView. Only one of the tabs showing the strange behavior: touching one of the NavigationLinks going to the next level view. When coming back (via back link in Navigation Bar) the Navigation Bar keeps showing overlaid with the original.

Anybody with similar experience and a solution ?

Here a screenshot: sorry, cannot post it here :-(

Here the code for this view:

Code Block 
[...]
    var body: some View {
            NavigationView {
                ScrollView(.vertical) {
                    
                [...]
                } 
                .navigationBarTitle("My Properties")
                .navigationBarItems(leading: Text("Level: \(player.level)").font(.headline).foregroundColor(.orange), trailing: Text("$ \(player.capital)").font(.headline).foregroundColor(.orange))
                .sheet(item: self.$selectedProperty, content: {property in
                    PropertyDetailOwnerSheet(property: property)
                        .environmentObject(self.player)
                })
            } 
            .onAppear(perform: {
                _ = self.timer
              })
              
    } 
[...]