CsWinRT: System.ObjectDisposedException when using the MediaTranscoder class

I use the MediaTranscoder class to convert a stream of bitmaps to a video file. This works fine when using .net core 3.1, but fails when using .net 5. After supplying a few frames, a System.ObjectDisposedException is thrown in System.Private.CoreLib.dll. The stacktrace is shown below:

at media_transcoder_test.MainWindow.StartMediaTranscodeSession(String outputFile, UInt32 videoWidth, UInt32 videoHeight, UInt32 framerate) in media_transcoder_test\MainWindow.xaml.cs:line 128 
at media_transcoder_test.MainWindow.Window_Loaded(Object sender, RoutedEventArgs e) in media_transcoder_test\MainWindow.xaml.cs:line 35
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__140_0(Object state)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.DispatcherOperation.InvokeImpl()
   at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
   at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object obj)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Windows.Threading.DispatcherOperation.Invoke()
   at System.Windows.Threading.Dispatcher.ProcessQueue()
   at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.Run()
   at System.Windows.Application.RunDispatcher(Object ignore)
   at System.Windows.Application.RunInternal(Window window)
   at System.Windows.Application.Run()
   at media_transcoder_test.App.Main()

I have attached a repro project that generates up to 200 (empty) frames and tries to generate a mpeg-4 video out of them. When started using vscode it fails after around 100 frames on my machine. It also fails when started without debugging. Interestingly, this repro project finishes on my machine when running under the visual studio debugger so I suspect some kind of timing related issue. media_transcoder_test.zip