Trials Master Boss Fight

Okay I dont know how to explain this, I was near the edge of the trialmaster arena and he stopped time and it just wouldn't continue the fight. Like nothing happenned. When I went back to the character select screen and re loaded it put me back at the Encampment.

just had the same thing happen to me, just as the boss was about to die he did his ultimatum and everything stood still, had to exit game. and everything gone when logging back into game.