Other mistake: When the clock is first shown in "Dances," the time is 7:40, but the title card reads: "1 hour 40 minutes until 9:00."
Sick Days & Spelling Bee - S1-E6
Other mistake: Vincent Martella plays a bit part as "Scoop", a newspaper photographer. His name is misspelled in the end credits as "Vincent Matella."
Computer Labs & Backpacks - S1-E9
Other mistake: In "Computer Lab," when Cookie is scanning for his locker, the exact same locker is scanned as both "Not Yours" and "Locker Located."