One run in Brayflox's Longstop, I had a BRD who refused to attack what the PLD was attacking, and pulling aggro all the time. I was getting tired of this, and started marking the enemies. This BRD still refused to attack the correct target, so I stopped healing them... sadly, Selene wouldn't, and so the BRD remained doing it. Eventually, mid-fight, I ordered Selene away, and just let the BRD die, then deliberately slow-cast Resurrection on them (once the fight was over). They seemed to get the message after that, the rest of the run went without incident.