Scoreboard doesn't count kill/assists correctly

If I keep track of my own kills/assists, it is often significantly different from what the scoreboard shows, both on the "personal" and "scoreboard" tabs.  It's no wonder that people are reporting that challenges aren't keeping track, either.  I find it hard to believe that the game programmers got some of the really hard stuff about designing a game right, where something that should be really basic programming, like counting kills, is so wrong.