Trialmasters challenge stuck if you kill the boss before passing the Trialmaster

I leapslammed down to the bottom level of the last fight vs the chimera, didn't pass the Trialmaster or start any dialogue with him.

Boss spawned, none of the effects that i had selected from the previous trials activated (i had the one that slows you then stuns you after a while, for example)

Once boss was dead, loot spawned but no quest completion. Ran back to where the trialmaster was and he activated, but quest has not progressed - and i cannot enter the door leading to the final room.