Winning Through Intimidation - S1-E15
Deliberate mistake: In the actual card game, attacking the castle ring would not be allowed, but this is probably done in order to enhance the show for kids.
Formidable Enemy!? Mother Coordinator Enters! - S7-E37
Deliberate mistake: This Pokémon Trainer's Choice segment incorrectly claims that Arbok evolves into Seviper, which isn't true. (00:11:38)