I did not see this hang reported yet?:
At the beginning of my turn Atzal, Cave of Eternity converts three gems.
Because of that some gems combine and this again triggers Atzal, Cave of Eternity second ability - to bring back he first creature of my graveyard to the battlefield.
Then the game hangs when I have to select which creature to replace, as I already have 3 creatures in play.
I can select a creature to be repolaced, I can even bring up the card details, but hitting one of the buttons of the incoming creature does nothing.
I can bring up the Pause screen. There hitting the battle log button does also nothing.
The only button working was the quit the game button 
But there was more going on to lead to this hang I guess. Because the creature to be brought back into the battlefield was a green dinosaur. And I played Sorin - definitely without any green Dinosaur.
//Edited Title - Tombstone