It is so disaster with Brann Tank! Dont make Brann Tank moving once you grab some mobs coz Brann keeps pulling new packs while moving. 60-100 yards where mobs are and it was safe but still lerroy more packs. Make Brann Tank stay while tanking those mobs! You have only 2 alternatives! Delete Brann tank or fix it!
I think Brann pulls across floors in Sidestreet Sluice, but it could also be the chain lightninig of Pocket Factory. That’s really the only place I have had “disasters” with him on my healer. It may look like he’s running away on his own, but he’s going for the mobs that pulled from the floor above or below and are pathing back to you.