Hiwada Gym! Forest Battlefield!! - S3-E28
Character mistake: Ash's Chikorita is knocked out by Bugsy's Metapod in the Gym battle against him. Brock mentions that Ash's remaining Pokémon are Cyndaquil and Pikachu, and Ash says, "I'll save Chikorita for later and use Pikachu now." However, Chikorita is the Pokémon that was just defeated, and Ash's remaining Pokémon is actually Cyndaquil, as mentioned by Brock. (00:11:20)
Happinas's Happy Nurse! - S3-E13
Character mistake: When Jessie asks if she can go to Pokémon Nurse School to become a nurse, the flyer she holds misspells Pokémon Nurse School as "Pokemon Nurse School." (00:07:53)
Lizardon Valley! Until We Meet Again!! - S3-E18
Character mistake: When displaying the title card in the English dub, it says "Charizard's Burning Ambitions," but the voiceover incorrectly says it as "Charizard's Burning Ambition." (00:02:21)
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.