Android: Exceptions in Background Tasks are silently caught

I am testing exception handling in my Xamarin.Forms App. I have to buttons that are bound to two commands.
One raises an Exception on the UI thread, the other one is rasied in a background thread.

throw new Exception("Testing application wide ui exception handling.");

vs

Task.Run(() => {  throw new Exception("Testing application wide background exception handling."); });

In my MainActivity, I am subscribing the uncaught excption handlers

AndroidEnvironment.UnhandledExceptionRaiser += OnUnhandledUIThreadException;
AppDomain.CurrentDomain.UnhandledException += OnUnhandledBackgroundThreadException;

Now, when i click to raise the exception on the UI thread, OnUnhandledUIThreadException is called.
But, when i click to raise the background exception, the exception is never raised somewhere. The OnUnhandledBackgroundThreadException is not called, and the application is still running.

Anybody knows whats going on?