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.
Plot hole: Why did Mikey jump to make the feathers fly if Vince said to abort? When TJ gets hit by the feathers, he's on the 'X marks the spot.' But when he got honeyed, he was nowhere near it. Before TJ gets feathered, He gets up onto his feet, like he had fallen down. But he was still standing when Mikey fired the feathers.
Continuity mistake: In the time before King Bob tells his story about being the Prankster Prince, no one is on the jungle gym except TJ and his friends. But after Bob finishes, around 20 kids are on the jungle gym, plus TJ and co. There was not enough time for ALL those kids to get on top of the jungle gym from the time King Bob started his story to the time he finished.
Plot hole: Hustler kid tells Gus in this episode that hustlers never deal in things that could get a kid in trouble. In the episode where all the kids need to become Ashley's he has no problem in handing out plenty of fake IDs, and at the beginning of every show he is shown displaying dodgy merchandise to a kid inside his jacket.(the kid isn't inside the jacket...the merchandise is...).
The Spy Who Came In from the Playground - S4-E4
Other mistake: When the gang is showing stone their way into the school they go through a vent and all of them manage to squeeze through the small hole in the wall.
The Spy Who Came In from the Playground - S4-E4
Continuity mistake: After the part where Mikey gets double portions, the school clock shows it is half past one, but a couple of shots later shows the clock at half past ten, what kind of clock does that?
The Spy Who Came In from the Playground - S4-E4
Continuity mistake: When the superintendent arrives at the school, he looks towards Stone who gives him a thumbs up. When he does this, Stone and the group around him are on the steps right in front of the entrance to the school. A couple of shots later, the entire group has suddenly appeared in front of the window without time for all of them to have moved.
Continuity mistake: When Agents Barnes and Noble are passing out the test, there is a boy in a green hat sitting in front of a girl with long hair. The next shot is of the same boy asking if he can use a pen, but now there is another boy with blond hair right behind him.
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.
The Madness of King Bob - S4-E9
Character mistake: Whenever the Hustler Kid delivers Randall's prize in the beginning, he says, "Grand prize delivery for Mr. Randall C. Weemes." But Randall's middle initial is J.
Call Me Guy - S4-E10
Factual error: When Gus walks in, all kinds of kids have their backpacks on, like they just got there. Then Jordan asks Gus when he got there, which was 7:58, just a couple of minutes ago. Then TJ says, "Who's up for some kickball?" But it is already after 8:00, meaning they would be late.
Continuity mistake: In this episode, it shows Randall in Miss Grotke's class, but in every other episode, it's never shown him in there.
Continuity mistake: When Randall's dad is talking to the gang about what Randall's been telling him about them (when they are outside, in front of the bouncy thing), his moustache disappears mid-sentence (in a close-up of him) and reappears in the next shot.
Factual error: When Gretchen is typing the pardon on Mrs. Lemon's typewriter, the paper that she is typing on doesn't go up and out of the typewriter gradually as it should. It goes up all at once when she's almost done typing.
The Biggest Trouble Ever - S4-E13
Other mistake: When the court hearing is taking place, T.J. wears a tie with blue and red stripes. As T.J. says to the mayor, "Sorry, sir, may I say something?", the stripes on his tie change to the opposite color for one frame (not counting the stripes on the knot).
Continuity mistake: When Spinelli gets the ball to play in the field behind the trees, you can see lines that would indicate that the ball was a basketball. However, when the kids are playing kickball, it's obviously a kickball.
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.
Here Comes Mr. Perfect - S4-E18
Continuity mistake: When Jared is holding his speech, Jerome's jumper turns blue twice.
Continuity mistake: Throughout the scene where Spinelli shows off her jump roping skills, the two Ashleys swinging the rope quite awkwardly and choppily go from a normal to a surprised expression every second or so.
Continuity mistake: When the marble gets knocked out of Spinelli's hands and it falls into the drain, the marble approaches the hole to the very left of the drain, but in the next shot, it falls into the hole right next to it.