I think the client disconnects and the app doesn’t saying anything.
I mostly play arena mode so this bugged happened to me more 6 times now.
Closing the client and turning it sometimes solves the problem. But mostly it is an automatic lose and it gots me frustrated.
Same here, happened 2 times during arena. The game got stuck saying its my enemy’s turn, there was no timer (rope), I waited a few minutes nothing happened, I did not receive any errors or disconnections. I could open the menu just fine and click on the environments. I forcibly closed the game after waiting for a while and re-opened it, I think it counted as a loss both times, while when it got stuck it didn’t change to “my turn”.
I think it also happened to my opponent during Tavern Brawl… game is bugged 
I think this thread is also related to the same bug:
Kil’jaeden endless turn however, I did not have Kil’jaeden - it does not seem to be related to this card at least in my games.
It happened again in my last game a few minutes ago, i didn’t know the bug was related to that card. The opponent played Kiljaeden just before the bug happened. Probably that as*face was aware of that bug and glitCHEATED" on purpose because he didn’t end his turn after playing it.
Happened to me during ranked match with no Kil’jaeden in sight. Exactly how the title says. I waited for a minute, restarted Hearthstone- poof, the star is gone just like that.