Game Mechanics: Pets not behaving properly when master is attacked.

[CupcakeValkyrie]

On classic live, if you ordered your pet to attack something, it would continue to do so unless another mob hit it enough to "pull agro" off of whatever its initial target was. I've noticed that on Green, however, if I throw my pet at Mob A, and then Mob B hits me, my pet immediately abandons its target and rushes to my defense, even if I don't want it to.

This isn't how it's supposed to work. Mob B hitting me should absolutely put it on my pet's hate list, but my pet shouldn't be abandoning its current target unless I specifically order it to "back off/attack" on the new target. In fact, a /pet back off should be required in order to get a pet to switch targets at all. Simply ordering your pet to attack a different target on classic live wouldn't make it switch targets. You always had to back it off first to get it to attack something else.

[Dolalin]

This is true from my memory. Getting hit wouldn't cause the pet to run over to the new mob. It would stay on its current target unless/until you ordered the pet to switch targets or the new mob started attacking the pet and building up hate.