I had a VSS equipped in my hands when entering a car to drive, and while driving the server crashed.
When I logged back in I was on the road with empty hands. The car stood nearby, but the VSS was nowhere to be found. Since this is hard to reproduce I do not know if being in a car with the weapon equipped when the server crashed is what caused it, or if it is just something that can happen whenever a server crashes. Should be investigated though, that VSS was my baby, she's kept me alive on that server for a long, long time!