The School of Hard Knocks - S1-E9
Revealing mistake: In the English dub, when showing the front of the flyer, it has filler text that is not related to what it is about. Also, its Poké Balls are slightly transparent and its picture can be seen through it. (00:05:43)
Charmander: The Stray Pokemon - S1-E11
Revealing mistake: When Brock passes Misty when he leaves the table she is at, he clips through her and the stool she is sitting on, and after he does, part of the former is missing. (00:07:08)
Pokemon, I Choose You! - S1-E1
Revealing mistake: When the second crowd is cheering, a woman's dress is not fully coloured in. (00:07:35)
Mystery at the Lighthouse - S1-E13
Revealing mistake: When the costume's right arm falls off, the shell is not fully coloured in. (00:12:32)
Mystery at the Lighthouse - S1-E13
Revealing mistake: As Krabby's Poké Ball begins wobbling, the light on it briefly shifts to the left. (00:04:36)
Mystery at the Lighthouse - S1-E13
Revealing mistake: When the costume's left arm falls off, the shell is not fully colored in. (00:12:33)
Revealing mistake: When Ash goes to save the Pikachu in the river, he clips through his and Misty's bags. (00:05:25)
The Water Flowers of Cerulean City - S1-E7
Revealing mistake: In the localizations, when Ash and Brock begin running to the crime scene, part of the top of Ash is missing. (00:04:25)
The Ninja Poke-Showdown - S1-E32
Revealing mistake: When Pikachu turns his head after a Venonat leaves, his left ear clips through Ash. Also, part of Ash's right leg is missing. (00:03:46)
The Path to the Pokemon League - S1-E8
Revealing mistake: When A.J. and his Sandshrew walk into a tent, A.J. and his whip clip through the tent. (00:07:56)
Revealing mistake: When Pikachu meets Puka on the cliff, we are treated to an aerial shot which shows the ocean below. There is sunlight reflecting off the surface, but as the camera moves, the lights pass in front of the two Pikachu on the cliff. (00:07:26)
Revealing mistake: When Ash brings his first piece of meat into his mouth, another one disappears into thin air. (00:09:09)
Tentacool and Tentacruel - S1-E19
Revealing mistake: When Brock says, "Ah! Zubat!" his neck is not fully colored in. (00:15:50)
Revealing mistake: As the camera pans up to Meowth in a crane, a building's windows move with the screen. (00:08:01)
Revealing mistake: When Team Rocket runs out of their cabin, Meowth's tail passes through a wall. (00:12:34)
The March of the Exeggutor Squad - S1-E41
Revealing mistake: When Melvin is throwing Poké Balls, they appear out of thin air before he throws them. (00:11:42)
The March of the Exeggutor Squad - S1-E41
Revealing mistake: When Misty tells Ash to stop looking at the Exeggcute, Ash's left hand is layered over the Exeggcute. (00:09:03)
The March of the Exeggutor Squad - S1-E41
Revealing mistake: When Misty tells Melvin to be careful, her left arm passes through the stage. (00:05:13)
Showdown at Dark City - S1-E40
Revealing mistake: When Ash apologises to the young boys, one of the boys' left arm is disconnected from his body. (00:02:09)
Showdown at Dark City - S1-E40
Revealing mistake: When the Yas Gym underlings send out their Pokémon to attack Ash, the Poké Balls disappear into thin air. (00:09:51)
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.