That fight had a lot of bugs on test that didn't get fixed. My friend had the same problem as you. My dad got the chest but nothing from the fight. Another friend got disconnected so no drops even though he finished the fight. Someone else said the cheats didn't stop when they were supposed to. I'm going to wait until it's fixed to do that boss on live.
It's kind of like reliving Ghost Avalon's unfixed Young Morganthe fight all over again, the one where she cheat casted too many Wooly Mammoths before. Ring a familiar bell on that?
