'Month' as a clue or part of a clue is perfectly fine because, as far as I know, we do not have any rule barring repeat words within a certain period of time.
I'd have to review the entire TFWG (as I prefer) Handbook but I left that behind in my former plush and cozy Game Czar corner office. My guess is that, by now, it was probably used by your intern, Kayla, or rcm's intern, or in one of the critters' litterboxes.