[GAMEPLAY] Killing jungle camps as Gangplank will make your creep score go down

As the title says, if you're Gangplank and kill a jungle camp the creep score shown for you is reduced by usually 30-40 cs. This appears for everyone in the game.

I've tested this in many games, and have a video showing how it works.

From what I've seen it doesnt usually happen until 15+ minutes, so to reproduce it just go into a game as Gangplank, farm for 15 minutes then kill a jungle camp and your creep score should go down. The reduced score also shows up in post-game history.