Backgroundservice refreshing memory usage on mainwindow causes exception on app shutdown

[vfib]

Hello,
Im using Net 9, Windows app sdk 1.6.4 and community toolkit mvvm 8.4.
This is my background service sending a message to my view model which sets the value in ui using UiDispatcherQueue.TryEnqueue.
Its added via services.AddHostedService();. Host is started via Host.StartAsync();.

PerformanceMonitorBackgroundService.cs

ShellViewModel.cs

When closing the program via X button I get sometimes following exception:

Error code: -2147418113
Stacktrace:
at WinRT.ExceptionHelpers.g__Throw|38_0(Int32 hr)
at ABI.Microsoft.UI.Xaml.Controls.ITextBlockMethods.set_Text(IObjectReference _obj, String value)
at Microsoft.UI.Xaml.Controls.TextBlock.set_Text(String value)
at Lm.Ui.Views.ShellPage.XamlBindingSetters.Set_Microsoft_UI_Xaml_Controls_TextBlock_Text(TextBlock obj, String value, String targetNullValue) in F:\C#\Lm\Lm.Ui\obj\x86\Debug\net9.0-windows10.0.22621.0\Views\ShellPage.g.cs:line 55
at Lm.Ui.Views.ShellPage.ShellPage_obj1_Bindings.Update_ViewModel_MemoryUsage(String obj, Int32 phase) in F:\C#\Lm\Lm.Ui\obj\x86\Debug\net9.0-windows10.0.22621.0\Views\ShellPage.g.cs:line 288
at Lm.Ui.Views.ShellPage.ShellPage_obj1_Bindings.ShellPage_obj1_BindingsTracking.PropertyChanged_ViewModel(Object sender, PropertyChangedEventArgs e) in F:\C#\Lm\Lm.Ui\obj\x86\Debug\net9.0-windows10.0.22621.0\Views\ShellPage.g.cs:line 365
at CommunityToolkit.Mvvm.ComponentModel.ObservableObject.OnPropertyChanged(PropertyChangedEventArgs e)
at Lm.Ui.ViewModels.ShellViewModel.set_MemoryUsage(String value) in F:\C#\Lm\Lm.Ui\obj\x86\Debug\net9.0-windows10.0.22621.0\CommunityToolkit.Mvvm.SourceGenerators\CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator\Lm.Ui.ViewModels.ShellViewModel.g.cs:line 26
at Lm.Ui.ViewModels.ShellViewModel.<>c__DisplayClass13_0.b__0() in F:\C#\Lm\Lm.Ui\ViewModels\ShellViewModel.cs:line 59
at ABI.Microsoft.UI.Dispatching.DispatcherQueueHandler.Do_Abi_Invoke(IntPtr thisPtr)

What can I do to avoid that? If other information needed, please tell me.
Thx and best regards