Originally posted by 2RAW4THESTREET
You never got kills on any other game type?
I think all the game type leaderboards are broken as once you hit level 50 you no long add to your score in that game type, the same thing has just started happening to a few of my friends now that they have also prestige.
Also if you look at all the different leaderboards other than score/career no one is higher than level 50, it seems like it's a glitch which will hopefully patched soon.