[Gameplay] Gangplank creepscore jumps up and down.

1.description: when i play gangplank recently, i notice the creepscore will change over time (for example, one minute ago i saw myself have 300+cs, but when i checked my cs 1 min later, the number become 280+).

2.it happens every game, but this bug only occur when it's post 30 min or so (don't know what is the exact time, but it doesn't occur at the beginning of the game).