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.
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.
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°.
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: 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.
Continuity mistake: Gretchen starts talking to that man who doesn't talk, but later when Mikey is singing for the first time, you see that man booing him, then a minute later Gretchen is still talking to him.