Boss bugged out of the map — can’t fix it

I’m having a serious bug and it won’t go away.

I was fighting the boss in Act 4: The Excavation (the final boss of the island). I died right when the boss was about to cast a skill. When I respawned and went back into the boss arena, the boss was still in the middle of casting — and then it completely disappeared from the map.

I can’t find any way to fix this. I really need the POE2 team to address this bug as soon as possible. I can’t progress the main story at all, and I’ve spent several days building this character. If anyone knows a workaround, please tell me — I really want to keep playing.