Flame Mage and Frost Mage summon their respective sphere pets which will attack a shopkeeper without provocation. That I can see as just a class limitation. HOWEVER, they also will NOT ATTACK a cockatrice. They have no bite or claw attack...their only form of attack is a suicide explosion, therefore there should be no limitations on attacking a foo-trice.
Also the starting pets for these classes (hell hound pups or winter wolf pup) will also spontaneously attack a co-aligned priest of the starting deity. Not only does this make any purchasing of AC via donation extremely difficult, it is not logical...why would a hell hound of Ash attack a priest of Ash without provocation?
I believe that the summoned sphere pets will also attack the co-aligned priests as well, but have not explicitly test this yet. If so, that is also I believe, not correct.