Other mistake: Near the beginning the dividing line in the bathroom has Henry on the right and Peter on the left but as you can see Henry would be on the left due to where his room is and where he would have to walk.
Party Animal/Ipso Fatso/Don't Yank My Chain - S1-E2
Other mistake: Party Animal: When Mime is reaching for a peanut in the blender, his arm and the peanuts are not actually inside the blender, but rather behind it. This same error with Mime's arm is shown again when it gets blended. (00:05:50)