While I played on the official DayZ server, It's happened that I started fighting with other people. I fired with FX-45 and when I started reloading (I pressed several times R, then holded R), it's stacked. I thought that the gun misfired or something like that, but the truth was different. Server and everyone else (my friend for example) see that I have FX-45 in my hands while for me I'm with bare hands or everything else.
When I reconnected, all was ok, but when I started to reloading again - I lost synchronization again.