ASP.NET Core SignalR Wait / Result blocks

While designing a web API I came to SignalR which seems to fit my demands having a persistent connection to the server which holds a state for the current client.

My problem is the "async - only" api.

I rarely use TPL and I used to synchronize async calls with .Wait() or .Result() which (I learned is bad practice) in a separate thread by message pumping and this worked for me so far.

I understood when using await, my code below can be executed on the same thread context as the ...Async() function which can cause a deadlock when using .Wait() or .Result when the same thread context is used.

But find the code below:

AutoResetEvent are = new AutoResetEvent(false);
private void Invoke()
{
  Thread s = new Thread(() =>
  {
    Task t = hubConnection.InvokeAsync("Sum", 5, 7);

    t.Wait();

    are.Set();
  });

  s.Start();

  are.WaitOne();

Invoke() is called from UI thread. This call starts a complete new thread in which the async call is performed. But also here, when calling .Wait() everything is blocked.

If we replace the SignalR call

 Task t = hubConnection.InvokeAsync();
 t.Wait();

by

Task t = Task.Delay(5000);
t.Wait();

it works as expected.

Can someone solve this puzzle for me? And how can I make real synchronous calls to that SignalR api

[Edit]

Meanwhile tried include async / await

See this code

AutoResetEvent are = new AutoResetEvent(false);
private void Invoke()
{

  Thread s = new Thread(async () =>
  {
    await hubConnection.InvokeAsync("Sum", 5, 7);

    are.Set();
  });

  s.Start();

  are.WaitOne();
}

This case also causes deadlock. How is this still possible? I think there must be a bug.