I have already read several complaints with this problem and unfortunately it happened to me too.

Yesterday I spent 5000 gems on an Aetherdrift Draft and in the second game in the middle of gameplay the screen got stuck in a "login/loading..." state and returned to the event lobby, which made me lose a life and the event without having played the game.

I then spent 750 gems signing up for another one, and the same thing happened again. This is intolerable. I demand a refund of both amounts spent.