Triumvirate of Terror! - S3-E8
Continuity mistake: As the camera comes out so Lex can broadcast the death of the heroes to the world and beyond, they are standing with Cheetah on Lex's right, and Joker to his left. But then when the shot shows a large screen where the broadcast is happening, Cheetah walks in on his left and Joker is now on his right. (00:18:00)