No offense, but you're completely misunderstanding me. I didn't want to write a wall of text in the original post and I didn't really think I needed to. But I'll explain this in more detail.
First off, my hunter here is my main and I'm quite well aware of everything they've done to pets and how they normally react to CC. I'm also quite aware that an elemental has nowhere near the tanking ability of a hunter pet or even a warlock's demon. That said, I do actually use it as a tank.
I have no interest in using my mage for much of any end game content (raids, arena, etc). When I found out how fast worgen skin, I decided I would make my worgen a farming toon. IMO, pet classes make the best farm toons. Long story short, a frost mage was the only pet class I didn't already have.
When I'm doing quests that involve mobs I can skin, I generally send my pet after the next mob while I walk up to the previous kill to skin it (in other words, I chain pull).
I use this macro.
However, if I'm chain pulling, I'm often out of range for my frost bolt (but this is intentional). So my pet goes to attack before I do. After I loot and skin my mobs, I finish the kill, rinse repeat and so on. Now that all that is out of the way, here's my problem.
The other night while questing, I had to polymorph a few mobs because they were a little closer together. So CC was actually necessary. However, when the mob that wasn't sheeped was killed, I would then set my pet on the sheeped mob. I did so by hitting that macro like I always do. But the elemental just would not attack it. I even tried CTRL-1 and still the elemental did nothing. It has nothing to do with stance. It just will not break the CC itself even though I'm commanding it to. As I said before, I'm fully aware that pets now react to CC. But I'm specifically commanding it to break the CC and it won't.