I (level 60 engineer) accepted a 'find-the-item' mission at the Avalon mission terminal next to the bank.
The mission is in Meetmedere.
I zoned into the entrance room and peeked into the first room: mission is of the type having a large, tall central room with posters on the walls. This central room contained three green engineer mobs.
I attempted to pull one engineer into the entrance room: all three noticed me, cast their pets, and followed me back to the entrance room, where they proceeded to pummel me.
Please note that three mobs with three pets is extremely challenging. I could not kill even one engineer, as I was forced to zone out and heal several times.
Out of desperation I re-entered the mission and bolted past the six mobs into the central room. I turned to see how many followed me, but instead saw multiple messages about "engineer attacks engineer for xxx points", and similar messages about bots attacking bots (alas, I did not think to capture any logs). After the messages stopped, I re-entered the entrance room to see three dead engineers, two dead pets, and one damaged bot standing there.
I'm assuming this is a bug. If it's a feature, however, I love it