Happens to me to... But I have noticed that it happens to other players at the same time too! it could be 2 or 20 other players who either drop their weapon, change to pistol, change to nade, change to nade and throw it which killz j00.

Server lag is usually to blame. But it could be another bug which happens rarely. This is v1.11.

P.S.
the code for your sig goes like this
[code:8558a]
[img]http://www.dodstudios.net/uploads/uploads/gpsdok.gif[/img]
[/code:8558a]
just copy and paste the text above
[img]http://www.dodstudios.net/uploads/uploads/gpsdok.gif[/img]