I’ve been using the Bogadile rune for the Piranhas spell, and I’ve noticed that when the Bogadile itself killed the last mob for a cursed chest in Act 4 in the Adventure/Bounties mode, it caused me to fail the quest, because I didn’t ‘kill’ the last elite mob, even though it was dead. Also, when the Bogadile killed the Act 4 Keywarden, the Keywarden didn’t drop any loot.