So me and a few of my buddies who have a couple of weapons with the "Firefly perk", keep experiencing game crashes from killing multiple mobs with precision kills due to the explosion I'm guessing. (Most common game crashing mob is multiple "Thralls" exploding.) I believe this was happening before the recent Hunter ultimate nerfing patch too. I can't pin-point any other source that may be causing the crash besides "Firefly."