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 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).
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.
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.
Other mistake: When the Ashleys are playing jacks, Ashley B is wearing her usual yellow sweater, but in the next shot, it becomes red, the wrong colour. It goes back to yellow in the next shot.
