Drop that horrid explosive rounds on fatebringer. That is what's causing it and it's nothing but trouble. Why would you need explosive rounds when every headshot causes a major explosion anyways? I have encountered outlaw not processing very occasionally, sometimes due to a critical and reload then another quick critical and reload, sometimes very rarely it doesn't activate with all the mayhem of fast reloads and multiple enemies and a lot of on-screen action but it's really rare. The old school guys have discussed this issue and its not necessarily a bug, it's that sometimes I'm guessing even a headshot with fatebringer the explosive rounds area of effect hits the target a split second after the headshot but before the target death registers, so the game thinks your final damage on the target wasn't a critical hit kill but a standard damage hit. The end result? All of us longtime fatebringer users run snapshot or field scout. FS only adds one round but it's my usual middle tier perk, just because i don't like the move faster when aiming down sites perk because I'm so used to movement speed when ADS with every other standard weapon. Just personal choice, although the switch weapons faster is worth it if you can adjust to increased movement speed when ADS. Test both and see what you prefer after lots of sampling.