Pet running back and forth

[Lil]

If I put my pet on assist, it sometimes returns to me for apparently no reason (as if I had called him back). After a short break, he runs to my target again.

Normally I don't mind this too much, but yesterday at the trash mobs before Lei Shen, I noticed my pet (I think it was my arcane wyrm serpent or the tallstrider) doing it constantly:
attack once, run back to me. attack once more, come back to me etc.
I thought: "maybe the pet automatically returns while their lightning shield is active", but I was careful not to damage a mob with a shield, and it happened nevertheless. I also made sure that it's not returning because I have a /petfollow in a macro somewhere by only using autoattacks... still my pet was running back and forth like rabid.

So, what gives? I don't particularly care about 4 trash mobs, but randomly losing pet uptime on bosses might get a bit annoying.

[Deleted]

I also encountered this problem during the Dark Heart of Pandaria scenario. I commanded my cat to attack the oozes that dwell in the cave, and he also leaped back and forth like he was using Rabid.
I had my pet on Passive all the time, but I don't think that has anything to do with this minor bug. While doing the Battlefield: Barrens quest, after the scenario, I didn't encounter the bug anymore.

[Deleted]

Call the pet off and give him an order to attack again (via pet bar). At least this trick worked for me.

My guess is someone f-ed BS coding and pet is trying to get minimum distance to use "teleport".

[Glurp]

I haven't noticed this at all. Having pet on assist is generally advised against in a raid because it will cause it to run around being stupid whenever you change target. Personally I leave my pet on passive and macro /petattack into my Arcane Shot.