@fattmedic You were onto something with the weapon switching. I tested it last night and found a way to repro the bug. Fire your primary, take out your secondary using any method of switching weapons, switch back to your primary and reload. One thing I'm not certain of is whether or not you need to fire your secondary before switching back.
Every now and then when I reload I notice that I don't load a new magazine, instead I load the same magazine. It hasn't happened recently, but when it was happening a few days ago I started making sure to let the reload animation complete and noticed that my magazine count didn't decrease. Just recently a friend had this happen to him when loading a shotgun. I'm not sure if this happens when speed reloading, if you walk while reloading, or if there even is a way to replicate this. Has anyone else encountered this?