Cartman Gets an Anal Probe - S1-E2
Visible crew/equipment: When Chef is singing: "I'm gonna make love to you, woman!" A crew member's hand can be seen moving the character's head. This was later fixed in the DVD version, but it was not fixed in the original version.
The Made-to-Measure Murders - S13-E2
Visible crew/equipment: A crew member's shadow is seen moving behind an open door that a character is walking by. (00:15:45)