>>394386713
That's just data being lost/ignored because you were busy connecting. Shot failed and Shooter is null are things that show up in the server log. It's been long speculated what they actually are but the speculation section seems to be our best guess.
Null shooter correlates with higher ping, unstable connections and players that to me are anecdotally more likely to trade kills. Leave something downloading in the background and you'll get high numbers here so the late packet answer seems sensible.
Failed shot is harder to pin down but most players can attest to shots sometimes doing no damage and unlike when the hitbox bugs out, it leaves no bullet holes behind. Some sort of UDP check makes the most sense to me but I also theorize that it's influenced by who you're shooting at. That would go some ways to explaining why the numbers can fluctuate so much from week to week for specifc players.

Either way it's all very enigmatic.