Continuity mistake: When Robin faces the Outworld Outlaw, he is still wearing his water skiing life jacket. But when the Outlaw is distracted by the grizzly and Robin moves in for the punch, the life jacket has suddenly turned into his costume's shirt again.
Continuity mistake: In the black and white family series, Beast Boy consumes half of an enormous stack of flapjacks. But when 7-Gorn-7 (literally) gate-crashes the homely scene, the stack of pancakes he disintegrates is taller than it was before.
X-X "The Lost Episode": Some other character cameos in the concerto audience include the two English ladies talking about fish in "Revolution", and Dr. Victor Payten, his interviewer, and the soap opera character Rebecca from "Episode 257-494".