The Forbidden Ritual: Part 1 - S3-E40
Continuity mistake: When Zane is telling Aster about how he never got to duel the Supreme King, there is a shot focusing on Aster where he is facing Zane, then turns his body 90° to look at the others behind him. Then it cuts to a wider shot, where Aster is facing the others directly and isn't turned away from them. Then he's back to his original position in the next shot. The next shot, he and Zane are side-by-side, even though he was supposed to be facing him directly in the previous shot. (00:04:40)