UWP: throw/raise not crashing the application, exception silently ignored - asynchronous

Question

I've found that my application is silently ignoring exceptions and I don't understand why.
I'll explain first the case that works: you create a blank UWP app, then reference an external library (in particular this library is implemented in F#), this way:
namespace MyApp.Frontend.UWP
{
public sealed partial class MainPage
{
public MainPage()
{
this.InitializeComponent();
MyApp.Frontend.App.Throw(); // <- I insert this here
var app = new MyApp.Frontend.XF.App();
LoadApplication(app);
}
}
}
The implementation of the method Throw in the F# side is pretty simple:
namespace MyApp.Frontend.XF
open System
open Xamarin.Forms
type App() =
inherit Application(MainPage = MainPage())
static member Throw(): unit =
raise (new Exception ("foo"))
...
This works well: the app crashes as expected.
However, if in a Xamarin.Forms app I throw the exception from within an async workflow, later capturing it in order to send it to the main thread (to make sure the app crashes), the exception gets ignored! (its exception type AggregateException just gets printed to the output, nothing else). The code for this new version of Throw is as follows:
namespace MyApp.Frontend.XF
open System.Threading.Tasks
open Xamarin.Forms
type App() =
inherit Application(MainPage = MainPage())
static member private CaptureException<'T> (task: Task<'T>) =
let nextTaskDelegate (prevTask: Task<_>) =
Device.BeginInvokeOnMainThread(fun _ ->
raise prevTask.Exception
)
raise prevTask.Exception
task.ContinueWith(nextTaskDelegate, TaskContinuationOptions.OnlyOnFaulted)
|> ignore
static member Throw(): unit =
async {
raise (System.Exception("blah"))
}
|> Async.StartAsTask
|> App.CaptureException
...
This method of crashing the app (bringing it to the main thread with Device.BeginInvokeOnMainThread, and also throwing it in the current thread, just in case) works perfectly fine in other platforms (e.g. Xamarin.Android), but somehow it doesn't in UWP and I'm not sure why. How should I bring the exception to light?