Something I noticed with Alolean Vulpix as the starter is that the AI does not seem to realize that Powder Snow is a room-range attack. Is that a bug in the base game?
EDIT: I started messing around with sky temple and found there’s separate values for actual move range and AI move range, and indeed, powder snow is set so that the AI considers it a point-blank move. I assume it was like that in vanilla too - my suspicion is that it ends up being way too oppressive for the enemy AI to spam room moves at you so they’re nerfed somewhat for partner usage as well