A Differently Colored Yorunozuku! Catch It!! - S3-E38
Other mistake: When the Pokédex tells facts on Noctowl, Ash's right ring finger and the one above lack a separating line, making it appear as if they are fused together. Also, the angle created by the screen and the identifier is a 130° angle, but in the next shot, it is a 170° angle. Additionally, Ash's right index finger is at the top of the section with the screen, but in the next shot, it is more in the centre. (00:02:08)
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.