Diana Ross - S4-E23
Continuity mistake: When Diana Ross finishes her first song, the bird has both his feet on the ground; in the next shot, the bird has one leg raised, without enough time passing to do so. (00:08:45)
Mark Hamill - S4-E16
Revealing mistake: When Luke Skywalker is introducing his 'cousin' Mark Hamill at the end, you can tell it's a split screen by the fact that Luke looks right past him, even once he's on stage. (00:25:10)
