Steaming Springs boss arena - no escape!

Clip:
https://youtu.be/fLvEekKZISc

On killing the boss of a Steaming Springs the arena door did not open. Had to relog and enter through original map portal.
After clearing the rest of the map, i visited the boss room again - still with a door that was one way.

Did another Steaming Springs with a boss a short while later - no issues that time.