I've noticed while playing 0.84 Beta, that while prone i was turning to shoot someone and he randomly died and I got XP as though I had killed him, I've also noticed that sometimes I'd dryfire my gun and the same thing would happen.

I have noticed this too.
Might have been caused by lag though. I've only encountered it in multiplayer.

Problem with that, I'm playing on multiplayer on a high-end custom built pc that 99.99% never/ hardly ever lags Except for sometimes Sync errors on certain servers, but sometimes I dont lag when hosting my own, which is what i was doing at the time i had encountered this