It has happened to me a few times now that I died as Widow while I was using the SMG. When I respawn the SMG sound is still played even though I don’t shoot anymore. Only when I shoot once again with the SMG is the bug gone.
Small but annoying.
Also, if it is bound to two keys, when pressing both at once, sound overlaps for a second.
I have this bug during a long moment. And I changed my sound card and I didn’t experience it since this day.
It can be hardware too but it only a supposition.