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.
Revealing mistake: During the montage of Eric and Frankie's game of pool, at one point Frankie hits two balls that spin towards a pocket in unison. When both balls come to a stop, you can see a dent in the green ball where a wire or other device would have been inserted to keep the balls linked together.
A Kiss is More Than a Kiss - S3-E14
Revealing mistake: When Cory puts the talking teddy bear that Topanga gave him in the trash compactor, the bear screams and Alan and Amy come down to investigate. Amy opens the trash compactor door and pulls out a bear crushed into a cube, but if you look closely, you can see the original bear still in the trash compactor unharmed.
The Heart is a Lonely Hunter - S3-E15
Revealing mistake: When the news director is flipping through the booklet that is Arthur's résumé, you can see the pages are blank.
Revealing mistake: When Topanga emerges from the kitchen with more ice for Cory, instead of seeing the kitchen through the open doorway, you can see a wall with framed pictures, suggesting another set was there in place of the kitchen.
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.