Audio problem: When Randall says, "Way to hop, man." his mouth doesn't move when he says 'man' until after he's finished saying it.
Other mistake: When Spinelli tells Gretchen, "Gretchen, what colour is the sky in your world?", Spinelli's neck clips through her dress collar twice.
Continuity mistake: When Gretchen leaves the school building at the end, she leaves the doors open behind her, but when she catches the helmet that Spinelli throws to her, the doors are suddenly closed.
Other mistake: When Gretchen is in Kelso's Corner Store, Mr. Kelso tells her that if she thinks she got the money in the wrong way, she should just give it back. In this shot, part of Mr. Kelso's shirt collar is incorrectly coloured red; then it changes to its proper tan colour mid-shot.
Other mistake: When Gretchen enters Kelso's Corner Store, the blue and yellow bicycles are slightly cut off at the bottom of the screen.
Continuity mistake: After Miss Grotke writes "The Zen of Homework" on the chalkboard, she holds the chalk in her right hand, but it disappears in the next shot.
Continuity mistake: At the start, when T.J. tells Gretchen to save up her allowance so she can buy Ruddler's Red Rocket, Gretchen's helmet strap has vanished; then it reappears a shot later.
Continuity mistake: When Randall begs Gretchen to do his homework, Mikey says, "Tutoring is just another word for helping," and his backpack is green. A few seconds later, it changes to blue.
Continuity mistake: When Gretchen's mother first sees Gretchen doing homework, the paper in front of Gretchen has three lines on it. In the next shot, there is only one line on it; then the paper is completely blank in the following shot. Then, when Gretchen falls asleep on her desk, the paper has three lines on it again, and Gretchen's pencil has disappeared from her hand.
Spinelli's Masterpiece - S4-E27
Continuity mistake: When the kids are all on the jungle gym to see Spinelli's drawing, Jerome can be seen sitting on the bar of the swings. However, when everyone is cheering he has suddenly moved to the ladder.
Spinelli's Masterpiece - S4-E27
Revealing mistake: When the hosepipe bursts and Spinelli's picture gets ruined, the water rises up a few inches off the ground, but the school has a chained fence so the water should run out.
Bonky Fever - S4-E30
Other mistake: After Miss Grotke asks the class which founding person said that they can't tell a lie, it cuts to a shot that pans over to Mikey. In this shot, all the kids' legs are missing from under the desks. Most of the chair legs are also missing.
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.
Bonky Fever - S4-E30
Continuity mistake: When the gang arrives at Mikey's house with his birthday gifts, Gus wears a red bow tie. Then, when the gang walks up to the door, Gus's bow tie has changed to the same color as his shirt, then goes back to red in the next shot.
Bonky Fever - S4-E30
Continuity mistake: When the gang arrives at Mikey's house with his birthday gifts, note the colours of the gifts that Gretchen and Gus are holding. When the gang looks at Spinelli's gift, Gretchen and Gus's gifts have swapped colours, then they swap back in the next shot.
Bonky Fever - S4-E30
Continuity mistake: In the cafeteria, Mikey asks the lunch lady for more pudding for Bonky. When the lunch lady refuses, the clothing on Mikey's Bonky puppet has vanished, then it reappears in the next shot.
Bonky Fever - S4-E30
Continuity mistake: After the gang gives Mikey his backpack full of Bonky stuff, Mikey runs away from them, and he is heading towards two kids playing marbles. Then, when Mikey slips on the marbles, they have changed colour.
Bonky Fever - S4-E30
Continuity mistake: After the gang finds out that Mikey was sucking on a Bonky pop, they find his backpack, which is its usual green colour. Then, when they discover all of the Bonky stuff inside it, it has changed to red.
Bonky Fever - S4-E30
Continuity mistake: When the gang talks about Mikey's birthday party near the start, Gretchen's bicycle helmet constantly changes throughout the following shots. First, part of her helmet changes from purple to blue, then it's purple again and the straps vanish, then they reappear, then the helmet becomes red, then it's the correct colours again and the straps become blue, and finally, the straps change back to purple mid-shot.
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°.
