The Final Duel: Part 1 - S5-E37
Revealing mistake: When Joey asks Tea, "You gotta use the little girl's room?", after she stops walking, Bakura's mouth is missing from his face. (00:02:26)
Yu-Gi-Oh! (1998)
1 revealing mistake in The Final Duel: Part 1 - chronological order
Starring: Eric Stuart, Amy Birnbaum, Dan Green, Darren Dunstan
Genres: Action, Adventure, Animated, Family, Fantasy, Thriller
Duel Identity, Part II - S1-E30
Character mistake: Yugi mistakenly says if he doesn't get a monster out to defend himself Mai can attack him directly, which wouldn't be possible since the rules of Duel Monsters during the Duelist Kingdom arc forbade direct attacks on defenseless opponents. That rule wouldn't be implemented until the Battle City arc.
Seto Kaiba: I'm surrounded by superstitious nitwits.