A New Land! A New Adventure!! - S6-E1
Revealing mistake: In the English dub, during the "Who's That Pokémon?" segment, part of Lanturn's tailfin is cut off. (00:11:39)
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)
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)
Satoshi and Butterfree! Until the Day We Meet Again!! - S16-E33
Revealing mistake: In the close-up of Ash and Metapod running to the cliff at night, part of Metapod is cut off several times. (00:15:12)
Revealing mistake: In the English dub, towards the end of the intro, May is slightly transparent and Max's left arm can be seen through her. (00:01:54)
Okido Laboratory! All Members Assemble! - S8-E41
Revealing mistake: When Professor Birch says that Muk should play with the other Pokémon, his mouth briefly detaches from his face. (00:06:23)
Ancient Pokémon Rampage! - S10-E17
Revealing mistake: When Buneary jumps down from a rock, it passes through it. (00:01:39)
Ancient Pokémon Rampage! - S10-E17
Revealing mistake: When Ash's Pokémon turn after he compliments their battling, Turtwig appears to be floating in midair. (00:01:33)
Save the Lost Hippopotas! - S10-E44
Revealing mistake: When Ash and his friends are digging, Ash overlaps Brock. (00:14:52)
Revealing mistake: When Aipom runs off with the crown, its tail passes through a wall. (00:07:34)
Pokémon Contest! Yuzuriha Convention!! - S9-E17
Revealing mistake: When Jessie walks over to May after she wins against her, Mime Jr's eyes and mouth are briefly missing. (00:14:06)
Queen of the Serpentine! - S9-E13
Revealing mistake: When the title appears, it is duplicated. (00:01:17)
Try to Study! Pokémon Trainer's School! - S6-E15
Revealing mistake: When Anita says that Kenny does not care about Pokémon either, she is sitting in midair. (00:09:46)
Revealing mistake: When Ash and his friends run into the Pokémon Center, a line is briefly layered over them. (00:07:06)
Revealing mistake: As Seviper slips back into the bush after Torchic trips on its tail, the end of its tail is cut off. (00:03:16)
Goodbye Chicorita!? The Electric Labyrinth! - S4-E42
Revealing mistake: After Team Rocket enters the lift, Ash runs in place for a few frames in the transition to the next shot. (00:16:42)
Aim to Be a Metamon Master! Imite - S4-E17
Revealing mistake: When Pikachu joins the fight against Team Rocket, he passes through Mini-Dit. (00:15:51)
Aim to Be a Metamon Master! Imite - S4-E17
Revealing mistake: At the beginning of Team Rocket's motto and shortly after, James appears to be floating in midair. (00:06:49 - 00:07:30)
Revealing mistake: After Meowth tells his plan to Team Rocket, part of the rope Jessie is holding is missing. (00:01:46)
Revealing mistake: When Ash's friends run over to him, as he dives into the pool, Pikachu can be running in midair. (00:14:27)
Answer: He is a good guy but just found himself in a bad situation when he worked for Lysander. He didn't want him to harm Ash and his Pokémon when he was trying to get the special bond between Ash and his Greninja to work. He does leave Lysander and go back to being a good person.