Anyone noticed that when you put your pet on guard and then he attacks a few times, he is not returning to where you put him on guard duty at?
Yup, once he gets close enough to the guard point, he parks himself and that becomes the new guard point. Repeat that a few times, and you start to notice the drift. Of course, the drift can be in any direction each time, so he'll usually stay in the desired area for quite a while before needing correction.
I've noticed this as well. It begins to annoy me when I place my pet in a speciific location for my pulls. I have trouble pulling the mobs and placing them between me and my pet due to pet drift.