Deliberate mistake: S14 Ep13 Coon vs. Coon & Friends: in the South Park universe, Canadians are depicted as looking the same (beady eyes, stick legs, heads sliced in half). Since Justin Bieber is Canadian, he should look similar to Terrance and Philip instead of having a normal face and body.
Continuity mistake: When Mr. Garrison is carrying around his gun, it is not the wood finished gun with the wood colored hand grip that he bought, it was the other one that had the grey hand grip. (00:14:20)Sol Parker
Continuity mistake: When the handicapped people are on the bus, from a distance you can see that on the far window there is a kid nodding his head from back to front with black hair and when it goes into the bus you can see that the kid has brown hair and is nodding his head side-to-side. (00:04:30)Chaz1003
Audio problem: Near the end of the episode, where the boys are standing at the bus stop and Kenny (who is in a seizure trance) starts getting attacked by rats, Cartman yells, "Hey, get away. He's not dead yet", but it doesn't sound like Cartman (the tone seems more high-pitched.).
Plot hole: When Scott Tenorman shows the other kids a video of Cartman doing his "piggy" act, the angle of the video shot shows that it could only have been taken from the place where Scott was standing when Cartman originally did it - but Scott is seen at that time to have no video camera or any way to have recorded this.Moose
Continuity mistake: When Stan goes to see John Edwards, John Edwards's butler goes to get him. When the butler reappears (just before he pushes the buttons on the wall for the recorded voices), he reappears from the right of the archway. But John Edwards appears from the left of the archway when the voices are playing.
Audio problem: The animated Christmas movie the boys are making is really "the Spirit of Christmas", the movie Trey Parker and Matt Stone made before South Park. The dialogue recorded by the boys is the same as in the original (with a few changes, but when the film is shown later it's the original speech from "The Spirit of Christmas". You can tell by the way the voices are done, and the tone of the voices.