
Continuity mistake: When Ash and friends are after Assunta wins, a man in a blue shirt has his left hand raised, but in the next shot, it is not. (00:08:33)
Other mistake: Assunta's Ivysaur attacks Sparky too early, before the battle even started, not to mention Assunta haven't given it any commands during the battle.
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.