This was a nightmare on 20 last night and took forever. 2 people in my guild had to disband groups with pugs because they didn’t have the organization to do it.
First we had the obvious bug where we got him to 75%, didn’t spawn adds, had to kill ourselves.
So we went back, he stayed at 75% health, immediately he started doing his huge AoE agony attack, then spawned like 15 adds which didn’t despawn after we used the hammer, which is rather ridiculous at 20+ fractal levels fighting an AoE Agony boss + like 10 veterans and a bunch of normal mobs.
So we wiped a 2nd time. We went back, he now had 50% health and didn’t regen, all the adds were still there that we had to clear before agroing him, then he no longer did any agony moves and just stayed melee. We had to kite him to the corner so we didn’t have to fight him and the 15 adds that spawn every time and then we managed to hurt him 4 times, do the whole hammer thing, and only agro a few mobs when we went in to hit the seal.
This fight is so messed up it’s amazing. I did this fractal legit at 10+ before I knew about hitting the seal with AoE attacks, and it was never even close to this screwed up. Not sure how doing something simple like making the seal un-attackable completely screws up this boss, it’s not just adds not spawning the first time.