Continuity mistake: The gang hatches a plan and tells Dave that Sam is trapped in a cave-in, so Dave begins digging to save him. When Sam and Spinelli return with their ice cream cones, Sam's gloves vanish and reappear a couple of times while he is holding his ice cream.
Other mistake: At lunch, when Sam is using a spoon to shape his mashed potatoes on the tray, his right arm clips through the tray just as he says, "Maybe I should clear out the east wall like this." Then, when Sam says, "Maybe I should fortify the south side first," he's using the spoon to move the mashed potatoes on top of the tray, but his arm and spoon are under the tray, so it looks as if the potatoes move on their own. Additionally, when Sam states that he's so confused, the spoon held up in his right hand appears to vanish in the next shot.
Continuity mistake: After getting off the school bus, when Gus falls into the hole that Sam has dug in front of the school, he's wearing his watch as usual. As Gus sits up, his watch vanishes mid-shot; then it reappears on his wrist.
Continuity mistake: After Upside-Down Girl tells TJ he must do something about Dave, when the gang look for Sam and discuss the situation with him, the clock over the school doors repeatedly changes time between shots. Then, when Sam grabs the shovel and jumps back into the hole, the two hands of the clock vanish, only to reappear and change time yet again.
Continuity mistake: When the gang is playing marbles, there are seven marbles in the ring, with three black ones on the left and four orange ones on the right. In the next shot, there is suddenly a green marble on the right side of the ring, with a black marble next to it.
Bonky Fever - S4-E30
Continuity mistake: When Mikey asks the lunch lady for more pudding for Bonky and she refuses, Mikey falls down on his back and starts throwing a tantrum. A second later, he has turned 90°.
Continuity mistake: In the introduction, when TJ pulls the ball off Gus, Gus is covered in gum. When they are walking into the school, the gum has disappeared.
Continuity mistake: When TJ's friends climb on the jungle gym to try and take TJ's place, we see that Gretchen is the last one up and there is no-one on the bars behind her. But in the next long shot, Mikey is right behind her. Then when it shows a close-up of them, Mikey is gone again; then he reappears a moment later.
Continuity mistake: When The Library Kid speaks for the first time, you see a shot of the gang, T.J's hat and hair colour are mixed up.
Continuity mistake: When Mikey's music teacher gets engaged to the Spanish guy, her ring disappears between shots.
Other mistake: After Dave takes away Mikey's lunch tray, it fades to a shot of the school clock, and there is no 5 on it.
Continuity mistake: At the very beginning, Gus drinks his entire carton of chocolate milk. Then in the wide shot, his carton is white. Back to a close up, and it's brown again.
Continuity mistake: When Gretchen is playing with Cornchip Girl, she puts down a card which is the orange cheetah. but after she has talked to TJ, it has suddenly changed to a completely different animal.
The Legend of Big Kid - S1-E14
Continuity mistake: At the end of the episode, when the gang is caged, right after Vince gives TJ the baseball card, TJ's facepaint turns from blue to red, then back to blue. (00:08:35)
Continuity mistake: When Vince's family is eating dinner, Chad's bow tie changes at least twice from red to black.
Here Comes Mr. Perfect - S4-E18
Continuity mistake: When Jared is talking to the whole school about shunning him, his undershirt changes from white to blue to white again.
Continuity mistake: When Library Kid sees her kindergarten class, she's wearing a dress, but when she runs into the library, she's wearing a T-shirt and skirt.
Continuity mistake: When TJ comes to school in the morning and everyone starts cheering, we see two Ashleys clapping with everyone else. As the camera follows TJ as he walks to the entrance, we see the same two Ashleys a second later.
Continuity mistake: When Menlo tells the crew about Randall's joke book, he loosens his tie, and it's still loose when he says "Indeed." But half-a-second later, as he walks away, his tie is back to normal.
Character mistake: When the kids are walking through the hallway, on the magician's poster, it says that he does Bar Mitzvahs. But the 'z' is missing, so it says Bar Mitvahs.