[GAMEPLAY] Visual CS Bug

During a game with my friends our Gangplank was CSing really well but his creep score was dropping frequently and raising back to where it was. This happened a lot and even in the post game lobby it displayed him as having at least 50 less than he had. Screenshots show him having 482 CS at 47:30 and 548 at 47:33. It has happened several times in several games but we've only noticed it on Gangplank.