Bullets_R_Us

This has been happening for weeks now. Every time i try to grind killing cops, i randomly stop getting XP for the kills. The "popups" saying +5 Kill, +5 Headshot, etc do not even appear and my level does not progress at all. This issue is completely random in terms of occurence, sometimes i dont even get XP for the first kill, other times i dont get XP after 15 mins of killing. The only way to fix this is to escape the cops and restart killing, or die and respawn. Even doing this sometimes i still dont get XP. This isn't limited to cops either, if i kill too many animals i also start to not get any xp. I cant find anyone else with this issue so can someone please help??