When Sid is first shown and before he asks Gerald to tell the legend, you can't see any hair in the gap in his hat just above where it snaps together, but later in the episode, you can.
When Gerald is done telling the legend of Stoop Kid after all the kids leave Robert is shown to have a different nose from what he had in the other episodes he appeared in.
Also Park’s ears are missing in that same scene.
Park's door was red when he dumped the trash on Arnold, but then it was blue when he came out asking "what's going on?".
During the night Stoop Kid is sobbing, Arnold's hair switched sides when he said people wouldn't make fun of him if he left the stoop.
Arnold's sleeve was red when he showed Stoop Kid the Spanish Steps in Rome.
Justin Shenkarow and Marcus Toji's names were misspelled in the credits as "Justin Shankarow" and "Marcus Togi", respectively. Also, two people are credited as "Storyboard Director", but the second (Tricia Garcia) should be credited as "Storyboard Artist".
There are points in the episode where Harold is drawn off-model.