It appears that when you have a (pc) mage fighting the (npc) Battle Mages in Drunder, the summoned mage pet (Bolt of Flaming Stone Servant) from Bolt of Flaming Stone (Rk. II is all that I have, but willing to assume it happens on all ranks) is added to your aggro list.
This wasn't an issue until I pulled too many and the alert came up that I was reaching the aggro / mob limit.
I don't find that this is a serious issue at all, but wanted you all to be aware of it.
Thank you,
-- Olde