Parrots will be parrots, first. It's unreasonable to expect them not to bite, or attempt to bite. It is a form of communication. Snickers communicated with extreme prejudice, but for a very good parrot reason.
Diffusing and essential oils have entered the companion animal arena with great success for some, and a sad end for others. The thing about diffusing essential oils is; it isn't essential. But it does require essential understanding.