Navigation works only once in my App

[xrth87]

Hello,
i am developping a simple calendar app for taking handwritten notes. With a day page a week and a month page. Week and month page contain a NavigationView for a Overview and a note for the month. Initially, the day page get displayed via a Buttons I can switch the page BUT the buttons only work one time.

1. Day -> Week works
2. but back to Day does not work only
3. Week -> Month does work.
4. But after this I neither can navigate to Week or Day

The ViewModels are registered as Singletons.
In my App.xaml.cs i do the following:

 private static void ViewRouteBuilder(IViewRegistry viewRegistry,
	        IRouteRegistry routeRegistry)
        {
	        viewRegistry.Register(
		        new ViewMap<DayPage, DayViewModel>(),
		        new ViewMap<WeekPage, WeekViewModel>(),
		        new ViewMap<MonthPage, MonthViewModel>()
	        );

	        routeRegistry.Register(
			        new RouteMap("Day",
				        viewRegistry.FindByView<DayPage>(),
				        IsDefault: true),
			        new RouteMap("Week",
				        viewRegistry.FindByView<WeekPage>()),
			        new RouteMap("Month",
				        viewRegistry.FindByView<MonthPage>())
		        );
        }

And in the Navigation Usercontrol I have three buttons with the Attached property ui:Navigation.Request="Day" ui:Navigation.Request="Week" and ui:Navigation.Request="Month".

I get the following Debug output when trying to switch the pages:

Uno.Extensions.Navigation.RouteNotifier: Trace: StartNavigation - Pre-navigation: - Uno.Extensions.Navigation.Regions.NavigationRegion
Uno.Extensions.Navigation.Navigators.FrameNavigator: Information: NavigateAsync - Starting Navigation - Navigator: FrameNavigator Request: Week
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: NavigateAsync -  Navigator: FrameNavigator Request: Week
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RedirectNavigateAsync - RedirectNavigateAsync: No redirection - Navigator can handle request (and parent cannot)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: Show - Invoking Frame.Navigate to type 'WeekPage'
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: Show - Frame.Navigate completed
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (0ms)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: CoreNavigateAsync - Region has 1 children
Uno.Extensions.Navigation.NavigatorFactory: Debug: CreateService - Adding region
Started Thread 12304
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: DefaultRouteRequest - Request is empty, so need to determine if there are default routes to navigate to
Uno.Extensions.Navigation.NavigatorFactory: Debug: CreateService - Adding region
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Elapsed navigation: 260
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation: (Frame)-FrameNavigator(Week) [(NavigationView)-NavigationViewNavigator [(Grid)-PanelVisiblityNavigator]]
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation (route): Week
Uno.Extensions.Navigation.RouteNotifier: Trace: StartNavigation - Pre-navigation: - Uno.Extensions.Navigation.Regions.NavigationRegion
Uno.Extensions.Navigation.Navigators.FrameNavigator: Information: NavigateAsync - Starting Navigation - Navigator: FrameNavigator Request: Day
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: NavigateAsync -  Navigator: FrameNavigator Request: Day
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RedirectNavigateAsync - RedirectNavigateAsync: No redirection - Navigator can handle request (and parent cannot)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (0ms)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: CoreNavigateAsync - Region has 1 children
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: DefaultRouteRequest - Request is empty, so need to determine if there are default routes to navigate to
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Elapsed navigation: 19
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation: (Frame)-FrameNavigator(Week) [(NavigationView)-NavigationViewNavigator [(Grid)-PanelVisiblityNavigator]]
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation (route): Week
Uno.Extensions.Navigation.RouteNotifier: Trace: StartNavigation - Pre-navigation: - Uno.Extensions.Navigation.Regions.NavigationRegion
Uno.Extensions.Navigation.Navigators.FrameNavigator: Information: NavigateAsync - Starting Navigation - Navigator: FrameNavigator Request: Month
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: NavigateAsync -  Navigator: FrameNavigator Request: Month
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RedirectNavigateAsync - RedirectNavigateAsync: No redirection - Navigator can handle request (and parent cannot)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: Show - Invoking Frame.Navigate to type 'MonthPage'
Loaded Assembly 'E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Uno.Core.Extensions.Disposables.dll'
Loading module E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Uno.Core.Extensions.Disposables.dll in application domain 1:clrhost
Pdb file for assembly E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Uno.Core.Extensions.Disposables.dll was not found or failed to read
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: Show - Frame.Navigate completed
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Started Thread 29212
Started Thread 28200
Started Thread 16196
Started Thread 832
Started Thread 26120
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (51ms)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: CoreNavigateAsync - Region has 2 children
Uno.Extensions.Navigation.NavigatorFactory: Debug: CreateService - Adding region
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: DefaultRouteRequest - Request is empty, so need to determine if there are default routes to navigate to
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Elapsed navigation: 1271
Uno.Extensions.Navigation.NavigatorFactory: Debug: CreateService - Adding region
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation: (Frame)-FrameNavigator(Month) [Month(NavigationView)-NavigationViewNavigator [(Grid)-PanelVisiblityNavigator](NavigationView)-NavigationViewNavigator [(Grid)-PanelVisiblityNavigator]]
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation (route): Month
Uno.Extensions.Navigation.RouteNotifier: Trace: StartNavigation - Pre-navigation: - Uno.Extensions.Navigation.Regions.NavigationRegion
Uno.Extensions.Navigation.Navigators.FrameNavigator: Information: NavigateAsync - Starting Navigation - Navigator: FrameNavigator Request: Week
Uno.Extensions.Navigation.Navigators.FrameNavigator: Debug: NavigateAsync -  Navigator: FrameNavigator Request: Week
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RedirectNavigateAsync - RedirectNavigateAsync: No redirection - Navigator can handle request (and parent cannot)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (0ms)
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: CoreNavigateAsync - Region has 1 children
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: DefaultRouteRequest - Request is empty, so need to determine if there are default routes to navigate to
Uno.Extensions.Navigation.Navigators.FrameNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Elapsed navigation: 20
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation: (Frame)-FrameNavigator(Month) [(NavigationView)-NavigationViewNavigator [(Grid)-PanelVisiblityNavigator]]
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation (route): Month
Loaded Assembly 'E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Uno.Core.Extensions.dll'
Loading module E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Uno.Core.Extensions.dll in application domain 1:clrhost
Pdb file for assembly E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Uno.Core.Extensions.dll was not found or failed to read
Uno.Extensions.Navigation.RouteResolverDefault: Information: DefaultMapping - For better performance (avoid reflection), create mapping for for path 'Note', view '', view model ''
Loaded Assembly 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Security.Cryptography.Encoding.dll'
Loading module C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Security.Cryptography.Encoding.dll in application domain 1:clrhost
Pdb file for assembly C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Security.Cryptography.Encoding.dll was not found or failed to read
Loaded Assembly 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Runtime.Numerics.dll'
Loading module C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Runtime.Numerics.dll in application domain 1:clrhost
Pdb file for assembly C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Runtime.Numerics.dll was not found or failed to read
Loaded Assembly 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Formats.Asn1.dll'
Loading module C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Formats.Asn1.dll in application domain 1:clrhost
Pdb file for assembly C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Formats.Asn1.dll was not found or failed to read
Loaded Assembly 'E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\C5.dll'
Loading module E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\C5.dll in application domain 1:clrhost
Pdb file for assembly E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\C5.dll was not found or failed to read
Loaded Assembly 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Collections.NonGeneric.dll'
Loading module C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Collections.NonGeneric.dll in application domain 1:clrhost
Pdb file for assembly C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Collections.NonGeneric.dll was not found or failed to read
Loaded Assembly 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Collections.Specialized.dll'
Loading module C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Collections.Specialized.dll in application domain 1:clrhost
Pdb file for assembly C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Collections.Specialized.dll was not found or failed to read
Loaded Assembly 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Xml.XDocument.dll'
Loading module C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Xml.XDocument.dll in application domain 1:clrhost
Pdb file for assembly C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Xml.XDocument.dll was not found or failed to read
Loaded Assembly 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Private.Xml.Linq.dll'
Loading module C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Private.Xml.Linq.dll in application domain 1:clrhost
Pdb file for assembly C:\Program Files\dotnet\shared\Microsoft.NETCore.App\6.0.11\System.Private.Xml.Linq.dll was not found or failed to read
Loaded Assembly 'E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Fizzler.dll'
Loading module E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Fizzler.dll in application domain 1:clrhost
Pdb file for assembly E:\Repos\UnoTest\UnoTest\UnoTest.Windows\bin\x64\Debug\net6.0-windows10.0.22000.0\AppX\Fizzler.dll was not found or failed to read
Uno.Extensions.Navigation.RouteResolverDefault: Debug: DefaultMapping - Created default mapping - Path 'Note'
Uno.Extensions.Navigation.RouteNotifier: Trace: StartNavigation - Pre-navigation: - Uno.Extensions.Navigation.Regions.NavigationRegion
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Information: NavigateAsync - Starting Navigation - Navigator: NavigationViewNavigator Request: Note
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Debug: NavigateAsync -  Navigator: NavigationViewNavigator Request: Note
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: RedirectNavigateAsync - RedirectNavigateAsync: No redirection - Navigator can handle request (and parent cannot)
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (0ms)
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: CoreNavigateAsync - Region has 1 children
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: CoreNavigateAsync - Request is being forwarded to 1 children
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Debug: NavigateAsync -  Navigator: PanelVisiblityNavigator Request: Note
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (0ms)
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: CoreNavigateAsync - Region has no children to forward request to
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Elapsed navigation: 26
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation: (Frame)-FrameNavigator(Month) [(NavigationView)-NavigationViewNavigator [(Grid)-PanelVisiblityNavigator(Note)]]
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation (route): Month/Note
Uno.Extensions.Navigation.RouteResolverDefault: Information: DefaultMapping - For better performance (avoid reflection), create mapping for for path 'MonthOverview', view '', view model ''
Uno.Extensions.Navigation.RouteResolverDefault: Debug: DefaultMapping - Created default mapping - Path 'MonthOverview'
Uno.Extensions.Navigation.RouteNotifier: Trace: StartNavigation - Pre-navigation: - Uno.Extensions.Navigation.Regions.NavigationRegion
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Information: NavigateAsync - Starting Navigation - Navigator: NavigationViewNavigator Request: MonthOverview
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Debug: NavigateAsync -  Navigator: NavigationViewNavigator Request: MonthOverview
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: RedirectNavigateAsync - RedirectNavigateAsync: No redirection - Navigator can handle request (and parent cannot)
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (0ms)
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: CoreNavigateAsync - Region has 1 children
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: CoreNavigateAsync - Request is being forwarded to 1 children
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Debug: NavigateAsync -  Navigator: PanelVisiblityNavigator Request: MonthOverview
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - start
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - start
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: EnsureChildRegionsAreLoaded - Making sure current view is loaded - end (0ms)
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: CoreNavigateAsync - Region has no children to forward request to
Uno.Extensions.Navigation.Navigators.PanelVisiblityNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.Navigators.NavigationViewNavigator: Trace: RegionNavigateAsync - Invoking control specific navigation - end
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Elapsed navigation: 18
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation: (Frame)-FrameNavigator(Month) [(NavigationView)-NavigationViewNavigator [(Grid)-PanelVisiblityNavigator(MonthOverview)]]
Uno.Extensions.Navigation.RouteNotifier: Trace: EndNavigation - Post-navigation (route): Month/MonthOverview
Exited Thread 18276

Unfortunately, I spend several hours now on navigation to get it work. Do you have any ideas what I am doing wrong?
Best regards,
xrth87