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.
Continuity mistake: When Spinelli is challenging the hustler kid, she asks for Gretchen's bow (for a blindfold). In the shots after that, Spinelli is still blindfolded with Gretchen's bow, yet Gretchen is still wearing it.

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: 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.
Continuity mistake: After it is explained that without Dave, Sam is unfocused, you see that he has dug holes just about everywhere. However, after that scene, all the holes disappear.

Schoolworld - S4-E21
Continuity mistake: The door to Miss Grotke's classroom opens inward throughout the episode. However, when SAL mimics Principal Prickly and tells all the teachers to report to his office, Miss Grotke leaves the classroom, and the door now opens outward. Then, when the kids look outside the classroom, the door has completely vanished.
Schoolworld - S4-E21
Continuity mistake: When Gus gets locked out of the school after recess, he asks SAL to open the hallway door. He looks up at the clock, and the time on it is 10.46.05 (then goes up to 10.46.08 by the end of the shot). A few seconds later, the time changes to 18.46.16, then 10.46.17, then 10.45.18.

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.
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.

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°.
The Secret Life of Grotke - S4-E32
Continuity mistake: When the gang are sat at the table before Miss Grotke comes on, the table is empty, but when Miss Grotke comes on stage, they suddenly have drinks.
Continuity mistake: In the beginning, Gretchen says she's short on money, so she can't get a chocolate milk, just a white milk. But, when T.J. walks by with his food, Gretchen has a chocolate milk, such is evident from the brown carton.
Suggested correction: Gretchen tells the lunch lady that because she is one penny short, she will swap the chocolate milk (in her hand) for a regular. She puts the milk on her tray and walks off screen. Then, when T.J. walks past her, the camera pans over to Gretchen watching T.J. with that same chocolate milk on her tray she is holding. Gretchen got distracted by T.J.'s encounter with the lunch lady and stopped to watch him, but she was still going to swap the chocolate milk for a regular later on.