This slip up can be found in Season 6 of Degrassi, episode 114, titled "Free Fallin". It is the episode that Paige discovers she is failing Banting and she has what appears to be a psychotic break at the end.

At the end of the episode, Paige is in her dorm, sitting on her chair. She pushes everything on the desk into the trash can, then throws a candle in and starts a fire.

Keep your eyes on the trash she throws in, two books, and what looks to be a small black bag or folder. Now keep your eyes on the contents when she throws in the candle, no sign of the small black object and now the trash is filled, not only with the two books, but with paper! When did she throw the paper in?