Continuity mistake: When Misty says that she and her friends have to go to Valencia Island, her bag disappears. This also happens at the end of the episode. (00:14:48 - 00:20:53)
Revealing mistake: When Ash tells Lapras to go back to the ocean, his left arm is transparent. (00:14:18)
Continuity mistake: When Team Rocket is eavesdropping on Ash and his friends, Meowth does not have a lei, but in the next shot, one appears. (00:09:06)
Continuity mistake: Right before Tracey says that Ash is heading towards a cliff, Pikachu's tail turns completely yellow. (00:19:13)
The Path to the Pokemon League - S1-E8
Continuity mistake: When Ash and his friends are standing in front of A.J.'s Gym, Ash's white sleeves turn blue. (00:02:45)
Continuity mistake: When Misty tells Ash that they should take a break, her bag disappears. This also happens when she says that they may be on a deserted island. (00:02:28)
Continuity mistake: When Ash tells Tracey to watch out, the strap on Misty's bag disappears. (00:06:30)
Tsubotsubo vs Madatsubomi - S4-E13
Continuity mistake: When Ash has a hunger pang, the orange stripe on his bag turns cream-coloured. (00:03:14)
Continuity mistake: When Misty tells Hoothoot to not give up, her bag disappears. (00:12:03)
Continuity mistake: In several shots, Misty's bag switches from her right shoulder to her left.
The Mandarin Island Miss-match - S2-E18
Revealing mistake: When Prima walks over to Ash and his friends, she is briefly layered between the table and Tracey. (00:03:06)
Continuity mistake: When Misty steps on Tracey, Tracey's blue shoes turn black. (00:02:13)
The Mandarin Island Miss-match - S2-E18
Continuity mistake: When Ash wins the match in the beginning, Tracey's orange bag turns green like Ash's. (00:01:12)
Continuity mistake: When Meowth says that he will use The Crystal Onix to make a charm, his white claws turn cream, like his body. (00:16:51)
Continuity mistake: When Tracey wonders why everyone is outside the museum, the black straps on his bag turn orange, like the rest of the bag. (00:05:29)
Continuity mistake: When the Officer Jennys say that the news reporters are Team Rocket, Meowth's disguise disappears. (00:12:31)
Continuity mistake: In several shots throughout the episode, the black straps on Tracey's bag turn orange.
Continuity mistake: When Daisy says that the Sensational Sisters have been performing for so long that they no longer get large crowds, Ash's left glove disappears. (00:04:38)
Revealing mistake: When Team Rocket runs out of their cabin, Meowth's tail passes through a wall. (00:12:34)
Attack of the Prehistoric Pokemon - S1-E44
Continuity mistake: When Ash says that Charmeleon still will not obey him, the green straps on his bag turn blue like his jacket. (00:11:06)
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.