Visible crew/equipment: When Topanga carries Cory into the room you can see a crew member's hand triggering the doors to open.
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.
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.
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.
Pairing Off - S2-E2
Continuity mistake: At the end of this episode when Eric & Cory are talking about Cory's date, Eric walks from his desk to the bed and we see the bedroom door is open, but when he walks to his desk from the bed the door is then suddenly closed.
She's Having My Baby Back Ribs - S7-E17
Continuity mistake: At the start, in Cory and Topanga's dorm room, Topanga asks if Cory thinks she is attractive. He says "Of course I do. Come here, I'll prove it" and leans on his side and tilted back. When the shot changes after Topanga starts walking towards the closet, he is suddenly sitting upright. (00:03:29)
How Cory and Topanga Got Their Groove Back - S7-E18
Continuity mistake: Cory is walking around taking back flyers he'd earlier passed out. In one shot he grabs a flyer out of a young man's hand but in the very next shot, the young man is still holding the flyer. (00:08:57)
Continuity mistake: When Cory is "The Coconut Guy" he is showing Jay Leno, David Letterman and Arnold Schwarzenegger. When Topanga comes to the shop Cory knocks the Arnold Schwarzenegger coconut down but in the next shot, it is perfectly straight up. (00:12:04)
A Long Walk To Pittsburgh (2) - S4-E17
Continuity mistake: When Topanga comes back to see Cory, for the whole period of time that she is there, sometimes her hair is dry and straight, and others it's wet and wavy. (00:07:12 - 00:21:16)
Continuity mistake: After Eric pulls the doll from out of the grill, he closes the lid. The lid then alternates between being open and closed throughout the rest of the scene. (00:03:44 - 00:06:15)
Continuity mistake: After Topanga draws a lipstick heart around her face and Shawn says "Use a mirror, babe," a closeup is shown of Topanga smiling at Shawn and you can see Cory has lipstick on his forehead before Topanga has drawn it on him. (00:20:30)
Continuity mistake: When Cory is getting food for Shawn, he's piling meat loaf onto his plate. There are three pieces, one on top of the other two, then they cut to a wide shot and back to a close up of Cory, and it's just one larger piece.
Revealing mistake: When Cory writes "Hey Dude" on the chalkboard, you can see how it had been written and erased several times, indicating previous takes.
Santa's Little Helper - S1-E10
Visible crew/equipment: After the bell rings and Mr Feeny says "Have a wonderful vacation," a boom mic can be seen dropping from the top left of the screen as the students are rushing out of the classroom. (00:17:20)
Visible crew/equipment: After Amy's C-section Alan walks into the waiting area, and just as his kids gather around him in the wide shot the boom mic dips into view at the top, center of the screen between Alan and the plant (viewed on iPad screen). (00:20:10)
Continuity mistake: After Eric smears his hands all over Topanga's face, the amount of skin cream on her right cheek drastically decreases when she is telling Cory she's going to go wash her face. (00:14:35 - 00:15:00)
I'm Gonna Be Like You, Dad - S7-E14
Continuity mistake: When Topanga, Shawn and Angela are hanging out in Cory and Topanga's dorm anticipating Cory's return from the doctor, the slice of pizza that Angela is eating goes from having a small bite taken out of it, to being halfway gone, and back to having one bite taken out of it. (00:12:07 - 00:14:02)
The War (1) - S7-E15
Continuity mistake: After Rachel sprays water all over Cory, the amount of wetness on his shirt varies throughout the scene. (00:05:53 - 00:09:05)
Continuity mistake: When Eric is hugging Angela, her arm is on his shoulder. In the next shot, when Jack is saying "How am I going to survive without money?" you can see, between him and Rachel, that Angela now has her arm on Eric's back. (00:16:58)
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.