A bunch of buildings in GDC completely lack tile collisions, mostly in the Residential District/Main Street/that place with the café.
Also, there's a weird bug where, if a Pokémon uses Wish, the game will skip the animation completely, cut to your turn, and next turn it will play the "X used Wish!" scene again, heal, then do it again for the new move.
Finally, I've noticed some really weird things with the battle terrains. Sometimes the opponent's pokémon won't attack at all, giving you basically endless free turns. I don't recall exact examples, sorry, but I do remember i