Not getting all my kills.

So lately I’ve notice that at times after a game. I don’t get the same amount of kills from my game play on to my challenges gauge. Example: In this game I got 36 kills but only 21 counted towards the challenge. Anybody know whats going on?

was your game type BTB heavies? You get 2 points for headshots, pummels, splatters and sticks but only counts as one kill. Hence the different tallys