A Kick-Ass Risky Business Party - S3-E1
Other mistake: Barry and Erica are watching Lany band with Beverly. They are hiding behind a bookshelf of board games. One of the board games is Showdown Yahtzee. This game did not come out until 1991.
Welcome to the Family Part 2 - S2-E25
Other mistake: Throughout this episode, Max is captured by villains and is about to be bitten by a vat of hermit crabs. It's pretty obvious that between every scene of Max, instead of the platform lowering, it's just getting higher. Clearly, Max should've got to the hermit crabs about halfway through the episode.
Other mistake: It is previously explained that Jake cannot grow a moustache, then a few seasons later Jake goes to prison and grows a moustache.