So I just did a nightmare dungeon.(Guulrahn Canals)
At the last objective to kill the corpse thingie, butcher also was there.
I killed the objective while battling butcher.
The invulnerable bubble spawned on top of me and the butcher, so in order to keep fighting butcher I instantly leave the bubble. This however made the butcher just instantly teleport into nothingness. I had spent maybe 10 seconds total with butcher in combat, so it’s not due to kiting him, nor is it due to fighting him for too long. This felt incredibly bad to see him dissapear.