Continuity mistake: At the end of the episode, when Alan is about to eat the cookie and Amy shows him what she is wearing, he drops the cookie onto his stomach. Later when Amy whispers something in his ear, Alan gets up but the cookie is gone.
Other mistake: When Cory and Shawn are auditioning for "Guys" and they're talking about the first person they pick, Cory says,"He's shorter than me and..." but after they pick both guys and he's talking to them, you can see that Cory is the shorter one.
Revealing mistake: When Cory and Shawn are holding band auditions, if you watch the guy that is shredding on guitar, you can see that although he is moving his fingers all over the fret board, his picking hand remains motionless, showing that he isn't actually playing and the sound was added in post production.
Continuity mistake: When Eric is talking to his tutor in the hallway after recieving an A- on a test, there is a poster in the background for Sex Ed. This changes though, from saying "Sex, Ed?" to "Sex Ed" throughout the scene.
Continuity mistake: At the end of this episode, you see Griff standing with Joey and Frankie. He's wearing a jacket over a pink button down shirt that has a red collar and red accents. He sees a girl, and the camera moves to Joey who stands up on the bench and screams at the girl, then when the camera goes back to Grif, he's wearing a jacket over a plain old faded red shirt. I wonder what happened to the other shirt.
The Thrilla' in Phila' - S2-E21
Audio problem: When Joey is saying "Frankie, tag me," his mouth movement is not synchronized with the dialogue.
Continuity mistake: Shawn steals some fruit just before the interview starts. He empties the whole bowl into his backpack. When the interview starts, the bowl is full again, with the exact same fruits that were just taken by Shawn.
Character mistake: After the production assistant walks away from the catering table, he walks into the area where the Matthews are being interviewed. Any production assistant would know better than to just casually walk right into the shot when a live televised interview is going on.
Continuity mistake: When Shawn is loading up his backpack with food from the catering table, a production assistant emerges from the kitchen and asks him if he's part of the interview. After Shawn says he is, the assistant walks away towards the front door. When the shot changes to the couch where the family is being interviewed, the assistant is nowhere to be seen, even though he walked right into the area of the shot. When the shot changes yet again, the assistant is back by the catering table, standing with his arms folded.
Continuity mistake: In this episode, Turner goes into a room and says it's his bedroom. But in "My Best Friend's Girl" Cory goes into that room and they say it's a closet.
Continuity mistake: In this episode Cory has a full length locker, but in the previous episode (Hometown Hero) He has the top locker. It's always in the same stop, so there is no way that he changed lockers.
Truth and Consequences - S3-E7
Continuity mistake: When they catch Janitor Bud on tape, there is a time clock on the wall. Through the rest of the episode there isn't.
Truth and Consequences - S3-E7
Plot hole: In this episode, it is discovered through a scientific study that Eric does not dream, and in fact doesn't even register brain activity while he is sleeping. However, the season 2 episode "Wrong Side of the Tracks" features a subplot where Eric listens to a motivational tape while he sleeps so he can learn to ice skate, and he dreams of Nancy Kerrigan giving him a lesson.
Revealing mistake: When Amy steps into the living room and sees Reginald, you can see a plain white wall behind the door that leads into the kitchen, when you should be able to see the kitchen itself, which would suggest another set was placed there and they didn't move it for the filming of this scene.
The Last Temptation of Cory - S3-E9
Continuity mistake: When Shawn walks out of the front door of the Matthews' house, you can see some diamond fencing with vines on it on top of a brick foundation. But establishing shots of the house show no such feature by the front door.
The Last Temptation of Cory - S3-E9
Deliberate mistake: When Cory calls Topanga from Missy's phone, he starts having a conversation with her as soon as he finishes dialing her number, with no time for the lines to connect.
Deliberate mistake: When Alan is trying to rush Amy out of the door, she yells from upstairs that she's still shaving her legs. A mere 20 seconds later, she comes downstairs wearing a dress and nylons. Even if she was for some reason shaving her legs while wearing a cocktail dress, that still wouldn't be enough time for her to clean off her legs, put nylons on and then walk downstairs.
Answer: Topanga's middle name is never specified. Considering her sister's name is Nebula Stop-the-war Lawrence, Topanga's is probably something equally unusual.