Hi there! It sounds to me like a straight legit Palcity mew you have there, so nice find! =D It pretty much adheres with the details you've shown me there (right pokeball, nature, ribbon, moves etc.), but it does seem strange that it caused problems transferring. The OT Name ought to be: パルシティ
And you might do well to double-check its stats, but nothing seems dodgy there =S If you still have problems, I think there's a hack-checking thread somewhere on this site =) Course, I'll be happy to do my best to answer questions too,
Pirate