CS Count on Gangplank Glitched?

I was playing Gangplank after it was re-enabled and I noticed a really strange bug. The game was 42:49 long and I totalled around 440 CS at the end of the game. However, my CS was bouncing around wildly (I started noticing it at the 35 minute mark). Sometimes it took away CS from my count and gave it back.

It's pretty difficult to explain this without screenshots but understand that it was pretty confusing and has never happened to me before. Could this be because of the GP bugfixes?