Fierce Battle in the Monster Ball Factory! Pikachu VS Nyarth!! - S18-E34
Revealing mistake: When Ash and his friends put all their Poké Balls in the case, Bonnie's hands are briefly drawn like Clemont's. (00:03:04)
Fierce Battle in the Monster Ball Factory! Pikachu VS Nyarth!! - S18-E34
Revealing mistake: After Pikachu points to Ash's friends, Ash's left hand passes through him. (00:17:39)