Part-Time Friends / Bio Square - S2-E19
Continuity mistake: Part-Time Friends: When Arnold and Gerald get part-time jobs at the flower shop, while Mrs. Vitello explains things to them, she asks if she's going too fast, and in the next close-up, Arnold's apron vanishes, then it reappears.
Part-Time Friends / Bio Square - S2-E19
Continuity mistake: The kids' teacher in "Bio Square" is Miss Slovak, who was their teacher in the first season, but in the first episode of this season they had a new teacher, Mr. Simmons.
Suggested correction: Other than the few episodes that take place at a specific time; this series is not meant to be taken in chronological order. Just roughly during the same 4th grade school year.