I actually just had the same issue yesterday with a VSS w/ PS01 scope upon logging into the server and right clicking to aim for the first time. The weapon was on automatic at the time. I dropped the weapon on the ground to pick it back up again and that seemed to fix it. I also had a CR 550 equipped which I dropped and picked up again to be safe and it did not fire when I pressed right click. So far it's only occurred shortly after logging in.