I don't care about "getting it often". Get me a case that I can do 80 to 100 % of the time and reproduce it locally.
Does that mean you don't believe us? Anyways it sounds like really good customer support to tell your customers you don't care.
For me it's a nearly gamebraking bug, as I always forget to first fire a shot after respawn to see if its working. I really don't know why this is happening or how to reproduce it. It's sometimes just there after I respawn. So far it happend with the mosin nagant rifle and the smg. The main problem is that it sticks until the next map once it has happend. Every time I respawn, frist click nothing, second click shot.
My theories so far are: I encountered it most of the times when playing on a really loaded server 50+ Players. It only happend to me on Spartanovka. I don't remember it at the moment - I will look out for it in the future - but I think I was in the ironsights while beeing killed. The theory of DColt with Bolting sounds about right. Maybe it also happens when you get killed while reloading. I have never been autobalanced prior to getting this bug, so I cant comment on that.
I remember back in Insurgency (a HL2 Mod) it happend if you get killed while reloading, it was a pretty common bug. And was responsible for many teamkilling incidents at spawn. It's the only other game where I encounterd such a bug before.