Grimhaven Boss Arena inaccessible

Bug report Reference ID
2,604,893,585

Rolled into the area to start the Asinia intro animation, then backed out to clear the rest of the map. Now, I can't get into the arena to do the boss fight. The "arena" button on the red mist is not there. Map bricked.

Tried to port out and back in. Tried to use checkpoints to warp around the map and come back. Nothing made the "arena" button appear. Big sad.