I'm using examples from my most recent map edit, although I've seen this sort of thing even while being in an Xvehicle so it's worth noting.
When you kill someone else while driving, more often than not it says that person was killed by your vehicle... but not always.
Fairly often it says the person in the other vehicle was TELEFRAGGED by you...
...which isn't so bad, as you still get a point for it.
But every so often what happens is...
...you kill the other guy but it says they killed themselves and you get no points at all.
This may not be fixable, but I thought it was worth mentioning.