Diablo’s apocalypse does not proc while enemy heroes are caught in the Zagara’s maw. I do not know if this is intended, but if it is not, please fix this!
P.S. I just checked some videos online, and it used to work before.
This is intended. Enemies caught in Zagara’s Devouring Maw are put into Stasis/Time Stopped and briefly removed from the game. This status makes Heroes unaffected by ally and enemy effects until it wears off.