When the shots from behind aren't synced up to the voices

I've noticed that most people I watch TV or movies with either don't notice it at all or it just doesn't seem to bug them, but it's this really peculiar pet peeve I have. When they're using two cameras, and you hear both sides of the dialogue. But while camera one shows the back of Person-A's head while showing Person-B's face speaking, and then Person-A is replying in the same shot, I can always tell when it's from a different take by the movement of their jaw, head or hair. It's just synced up correctly and yeesh that just bothers me!