Treasures of Utzaal quest (act 3) bugged

Treasures of Utzaal quest (act 3) is bugged for me, no matter how many times I repeat it, relog, reset the instance or whatever the boss doesn't drop the required hammer quest item. No, it's not the known issue of him dying in lava, I'm killing him on solid ground and no dice.

Same stuff for me, im playing Lich