The March of the Exeggutor Squad - S1-E41
Other mistake: The Pokemon Exeggcute is shown evolving in to an Exeggutor naturally. But the Pokemon Exeggcute can only evolve into an Exeggutor with the use of a leaf stone. In the Japanese version, there is a mention that something in these woods causes Exeggcute to evolve without using the Leaf Stone (when Exeggcute evolves, James even mentions that there is no stone). However, as this was skipped in the English version, it creates a plot hole.
The March of the Exeggutor Squad - S1-E41
Continuity mistake: When Ash recalls Bulbasaur and Squirtle, his right glove disappears. (00:17:02)
The March of the Exeggutor Squad - S1-E41
Audio problem: When Jessie and James enter the box, they speak, but their mouths do not move. (00:12:30)
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)
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.