South Park (1997)

Worldwide Recorder Concert - S3-E17

Continuity mistake: In the episode with the recorder concert. When Cartman and Kenny come into the hotel room, saying that they've found the "brown noise", Cartman is wearing headphones and holding another pair in his hand. Then he suddenly has two extra pairs - he gives one to Kyle and one to Stan (and is still wearing one himself).

Worldwide Recorder Concert - S3-E17

Plot hole: When Cartman writes the "brown noise" onto the score for the recorder contest, the note he writes is an ordinary E flat note. If E flat was the brown noise, wouldn't it have already been discovered years before?

Moose ★

Worldwide Recorder Concert - S3-E17

Continuity mistake: When the boys are running to stop the concert a frame is seen where Mr Garrison and Mr Macky are saying "are those our boys" and though the previous frame showed the gang of 4 running to the stage. Stan and Kyle's hat can be seen standing next to the teachers.