My experience in Brayflox as the tank. Oh no.

For some bizarre reason, the AI of the healer went full freaky right before the second boss. I pulled the second boss, DPS followed but she... LITERALLY... STOOD... OUTSIDE... AND WATCHED ME FOR THE WHOLE 30 SECONDS. Then the room locked. The poor ACN tried to keep me up but it was no use. Wipe.
After killing Hellbender and opening the chest, the healer did a 180 and ran back at an unpulled group of mobs and started attacking them - forcing me to go back and get her...
Finally, because the AI is never targeted by AoEs in any of the dungeons - I was hit by every single poison puddle as the tank. And derpy healer apparently never wanted to cleanse until I had 4 stacks of poison.

I'm not particularly sure why this happened, as it was just the healer doing these really strange things. The DPS did no such things so I'm left scratching my head, positive it wasn't because I hit engage or disengage.