isActive not working to go back when three levels deep

In my app I am using NavigationLink.isActive to programatically go back by setting a bound variable to false. I was doing this several levels deep, and although I could initially go back, once I pushed several views onto the stack, and then went back, I found the back button stopped working on one of the pages.

I also noticed this error:

2021-01-13 18:02:26.660739+0100 Resolute[6210:333764] [Assert] displayModeButtonItem is internally managed and not exposed for DoubleColumn style. Returning an empty, disconnected UIBarButtonItem to fulfill the non-null contract.

This Stack Overflow page suggested setting the navigationViewStyle to StackNavigationViewStyle:

NavigationView {
    ...
}
.navigationViewStyle(StackNavigationViewStyle())

This both got rid of the error, and the back button started working (setting the isActive bound variable to false)