Other mistake: Michael is 40 in Season 2 ep. 20 (Papa Said Knock You Out) while Jr. is 16 in ep. 19, which could not be possible since he had him when he was 16/17ish himself.
Super Bike / A Mile in My Shoes - S2-E6
Other mistake: When Jorgen does wand-ups to Cosmo and Wanda, he counts 1,2,1,2,etc, yet when he does them to Timmy, he counts 1,2,3,etc.
My Overkill - S2-E1
Other mistake: When JD and Turk get coffee from the street vendor, Turk tips the cup at an angle which shows they are empty as it doesn't spill.
Other mistake: At the start of the line dancing scene where Ray Von is deejaying, if you have the subtitles on, it says the song is Hillbilly Rock, Hillbilly Roll by the Woolpackers. It's actually 5,6,7,8 by Steps. (I'm quite embarrassed I know that).
Other mistake: In the inside of the flat where Jack and Victor dine with Frank McCallum, on the left wall there is a window on the left and a door on the right. However, this is impossible in their block of flats as we see in the exterior shots - there are no balconies and the layout of the building makes it impossible for a door and an exterior window to be on the same wall. From the cast commentary.
Misadventures in Babysitting - S1-E8
Other mistake: When Mr. McGuire is trying to get back into the house to check on how Lizzie is doing babysitting, the lock chain is on the door, so he grabs a saw to cut through it. He begins to saw it - however he forgot to take the yellow cover off of the metal blade. (00:18:40)
Other mistake: Two Tiffs can be seen for a few seconds when King Dedede and Escargoon drive in.