I've had this problem happen a few times where the game is over (3 piled, last prov gone) but it doesn't end, and no one can do anything, including resigning.
My game #7737005 is currently stuck.
(I know that this can be fixed by doing "kick & resign" - but I should have won this game.)
The likely culprit in that case is Black Market, which is known to cause problems in some cases.