IDK..... I would be worried about heavy metal toxicity, or maybe a calcium deficiency? I wouldn't see it as something to not be concerned about. Has this just started suddenly? How old is Raspberry? It really does look neurological in nature, the behavior is with out cause.....it's not breeding, or play behavior, or territorial behavior.........many things can cause neurological symptoms, metal and hypocalcemia are the two the come to mind. Hypervitaminosis (insert vitamin here) is also very likely. But there are many other things as well. How well do you trust your vet?