Quote from unknownna
After some heavy testing I found another nasty player sprite and/or a coop spy issue and managed to reproduce it. Sometimes your client will think that other clients are firing their weapons when they truly aren't firing them. The weapon selection is desynced between the clients. It can look like your opponent is firing his chaingun when it's actually being selected on his end. You don't hear any attack sounds or see any bullet puffs, but decals are spawned. I recorded a demo of it with 3287.