Act 3 - -Treasures of Utzaal Quest is Bugged?

I'm currently in Act 3 on the quest "Treasures of Ultzaal". I've just killed the foragemaster in the Molten Vault and the quest directive is to "Pick up the Hammer of Kamasa".

I've tried several times and restarted the instance, but he's not dropping a hammer. I've tried turning off the loot filter as well, still no luck. Is it possible I accidentally vendored or disenchanted a quest item?

I've also killed him a couple times and ran the full length of the canal to see if it dropped in another area. No luck..

I can't see it anywhere! I cant progress my quest, any thoughts?