South Park Fans Can't Unsee These Major Mistakes
It is not uncommon for long-running TV shows to include at least a few continuity errors, plot holes, or other mistakes. "South Park" has been on the air for 25 years, so it is undoubtedly difficult for all the writers and other people who work on the show to keep track of everything that has ever happened on it. Plus, the show is so silly and absurd that a few continuity errors almost seem to blend in with the general nonsensical events of the show. Plus, sometimes, a few mistakes make shows or movies better.
However, there are still certain mistakes on the show that fans simply cannot unsee. These tend to be things like characters' names changing, contradictions in the timeline, and unexplained changes in characters' appearances or outfits. Even though "South Park" fans embrace the show for being ridiculous, unrealistic (although satirical), and even fantastical, they are still bothered by the types of mistakes where it feels like someone simply made a typo in the script or forgot to fix something in their drawing.
Fans seem to be most concerned about these mistakes and continuity errors
Movie Mistakes points out several "South Park" characters whose names change unexpectedly. Butters Stotch's (Matt Stone) dad's name was originally Chris, but it was changed to Steve Stotch (Trey Parker and Matt Stone). Jimmy's (Parker) last name is originally Swanson, but it eventually became Valmer. In Season 1, Sheila Broflovski (Mary Kay Bergman) and Sharon Marsh (April Stewart and Mary Kay Bergman) and originally both named Carol. On Reddit, u/thery-guy observed that Heidi Turner's (Jessica Makinson) name is Marcy in Season 3. On a "South Park" fandom blog, ArtisticFangirl added that Tolkien Black's (Adrien Beard and Gilbert Lévy) last name was originally Williams.
Unexplained changes in character outfits also seem to bother fans. Movie Mistakes noted that the word "chef" on Chef's (Isaac Hayes) apron often switches from lower-case to upper-case within the same episode. Also, in Season 1, Episode 1, the show seemingly can't decide whether Mr. Garrison's (Parker) glasses are thick or thin.
On Reddit, u/RackDiscprin pointed out that Eric Cartman's (Parker) cat, Mr. Kitty (Parker and Jay Leno), changes sex. In the episode "Cat Orgy" from Season 3, she is female, but in the episode about cheesing from Season 12, he is male.
Lastly, fans expect a consistent timeline within the show's universe. ArtisticFangirl wrote that a few episodes mention Kyle Broflovski (Matt Stone and William Coryn)'s family moved to South Park when he was three, but in "It's a Jersey Thing," they moved there while Sheila was pregnant with Kyle.