Just encountered the most amazing bug with the Brawler's Guild. A Monk was fighting Kirrawk. About ten seconds later, a second person(Death Knight, I think) got ported down and his next boss spawned, Fran and Riddoh. About ten seconds later, I got ported down and my boss spawned, Proboskus. We were able to attack(and be attacked by) each other's bosses, and when one of them went down(I believe it was Kirrawk) all three of us were ported out and got credit for killing our respective bosses.
This happened a couple of times in my Brawler's guild today, too. At one point, we had 4 fights going at once. Bruce, Ixx, Blat, and Milhouse Manastorm. It was quite a fight, until we all got ported out.
This just happened to me as well, and I got credit for helping someone else kill their boss in the arena instead of mine, thereby bypassing mine. Blizzard....What is this, and have I just gotten myself a ban? D: