While doing my teaching practice many years ago, I sat while the class teacher taught a spelling lesson - words derived from receive, including reception and so on and (I quote) "receptical". I kept quiet at the time (never correct a teacher in full flow!) but afterwards I mentioned that I thought it could be wrong and it was receptAcle (I said it, did not spell it out).
He went back to the class and publicly thanked me for telling him the right spelling, and wrote it up on the board - "receptacal". Should I have corrected him a second time, do you think?