The New Kid - S1-E2
Other mistake: At the start when the gang change the time on the clock in the classroom, it wouldn't control the main school clock, plus in every other episode the clock has been operated by The Box on the side of the school, as shown in " The spy who came into the playground".
Other mistake: At lunch, when the kid tells the gang that Spinelli's parents will be the first parents on the space shuttle, Gus's right elbow vanishes, then reappears mid-shot. (00:02:42)
Other mistake: At Parents' Night at the school, when Gretchen's parents walk into Miss Grotke's classroom, Gretchen's father clips through the door. (00:05:46)
Other mistake: When Spinelli's real parents arrive at Parents' Night, the shot is flipped: the potted plant and poster are on the opposite sides, the letter on the poster is mirrored, the door opens the opposite way, and Spinelli's parents are running in the wrong direction. (00:08:26)
Other mistake: When Spinelli's real parents arrive at Parents' Night, as Spinelli's mother tells Miss Grotke, "She just stopped wetting the bed this year," her necklace vanishes, then reappears mid-shot. (00:09:23)
I Will Kick No More Forever - S1-E11
Other mistake: When the gang goes to visit Vince in his house, it shows Vince watching a video of a kickball game. But kids most definitely wouldn't be able to bring a video camera into school, and it most probably would be confiscated by Miss Finster.
Other mistake: In the episode, "the peanut butter kid", he is always eating his sandwich and it always seems like he only took a bite out of it and sometimes it went all the way back to the top. How could that be, he couldn't be chewing the entire time.
The Great Jungle Gym Stand Off - S1-E21
Other mistake: When TJ says that he and the rest of the gang met at old rusty, it shows you a flashback and the kindergartners are wild, but they only became wild when Gus arrives later (as said in All Growed Down).
Suggested correction: It's not true. After Gus "changed" the kindergartners he was sent away from school.
This correction misses the point of the mistake. In "Recess: All Growed Down," when Gus moves to the school, the kindergartners are shown as "normal," but then Gus changes them to be wild, and they start to have torn clothes and paint on them. However, in the flashback scene in this episode, it shows the gang meeting on the first day (excluding Gus), and they have torn clothes and paint on them. This doesn't make sense because they only became that way when Gus moved to the school.
Other mistake: When the gang walks out of the school and Spinelli says, "I can't believe Gus didn't even show up for school today," Gretchen's dress is incorrectly coloured green. Two shots later, it is blue again, as it should be.
Other mistake: When Mikey enters the dance class and Spinelli says, "Mikey?", the letters on the door to Mademoiselle's office are mirrored; the background is flipped in this shot.
Other mistake: When the gang enters the Ashley's Clubhouse and catches the Ashleys and Randall taking the treasure, Ashley B's skirt is incorrectly coloured green. A second later, it is yellow again as it should be.
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: When Gus and T.J. are talking on the bench, as Gus says, "No, at least not yet," his watch is missing from his wrist; then it appears mid-shot.
Other mistake: When the Ashleys are first shown playing jacks, Ashley T's nose seems to be missing; then it reappears three shots later.
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: 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: 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.
Bonky Fever - S4-E30
Other mistake: When T.J. goes to Miss Finster to tell her about Mikey's Bonky stuff, Miss Finster's waistband is yellow when it's supposed to be white. Then, when she takes the bag from T.J., it has changed to pink, then turns white and back to pink mid-shot. Her collar is also yellow in this shot, then turns white and back to yellow mid-shot as well.
Beyond a Reasonable Scout - S5-E3
Other mistake: Phil the Scout ties a rope to Mikey's see-saw end's handle to lower Gus down without hurting him. Couldn't Mikey just climb off and hold the see-saw down with his hands and lowered Gus's end down slowly?
Suggested correction: Well, yes. He definitely could have done that. But I'd say that this belongs under stupidity, as they are defined as "stupid annoyances, like daft character behaviour," and this falls under that, to me. It's not really a "mistake" of any kind.