Happens about 18:20. Shot sound is heard, there's smoke from the muzzle, but no shot is fired. It occures when shooting in the exact moment enemy sniper recamoes. Opponent is now aware of my countersniper, but his sniper is still alive. In current metagame sniper wars it's quite an annoying and, in some games, gamebreaking bug.
I've seen this a few times. It's like any misfire bug really- there's a very small window between the firing animation and the bullet actually hitting a unit whereby the target can move out of range/invisible resulting in just the sound. Obviously, it's more annoying when you're going for a countersnipe, but I don't see it as gamebreaking.
