I'm having similar issues with this on watchOS10.
As soon as I add the .tabViewStyle(.verticlePage) to my TabView, my NavigationLinks start acting funky and breaking until I leave the view and come back.
I also get a view error in the console–
Snapshotting a view (0x100f3c2d0, PUICNavigationBarSmallTitleLabel) that is not in a visible window requires afterScreenUpdates:YES.