It continued after we all died and respawned back at brave haven, and on teleporting back to the area where we died, which was the copper monstrosity arena.
Me and my friends had this happen too; three of us died and it remained damaging us and spawning mobs after we revived everyone.
Pets can walk off ledges to float in the air too
It continued after we all died and respawned back at brave haven, and on teleporting back to the area where we died, which was the copper monstrosity arena.