Yes, you've trained her now to shark attack when she performs and you do not treat! Stop treating, or at least, every time. Keep her guessing when she'll get it. Otherwise, she'll do it for the treat and not for you.
More than treats, though, V's are addicted to your love and attention, do not minimize the reinforcing effects of a simple, hearty "GOOD GIRL!", or a "YAY!" and a quick smooch.