One thing to note that happened to me the other day. I left up my totems from the first fight and this caused two of the groups of mobs to aggro and attack me while I was healing up. Talk about a /facepalm.

However, it didn't end there. When I went back the group on the right was not in the original position, but staggered a bit and close to the middle group. Well, I went for it and all six mobs aggro'd. Maybe I just suck, but I sure got owned. My tank even got mind controlled! It was ugly.

I decided it just wait until it reset on it's own (i.e., if you wait long enough the "organizer" toon you talk to before each fight will appear and you just start the fight over).