i had it happen to me in Lower guk at both lord and frenzy camp.. charmed 1.. FDed and when my charmed mob dies, the other 2 attack eachother.. didn't happen every time.. but like 50% chance or so... maybe higher. but i had to be FD for it to happen. (ie out of agro from mobs)

Happening at Hate atm. Got feared while pulling, was sent running around until ended up in a house with a forsaken revenant, the revenant charmed me, and the next second the pack that had been chasing me proceed to start killing each other. Utter chaos ensues, mobs running all over the place ignoring players and butchering one another.

Interesting. So in this case, once you were charmed and became the Revenant's "pet", all the agro that was coming your way transferred to your owner despite the fact that they are on the same faction.

That certainly puts a new spin on things.

So it seems there are multiple ways to cause this.