I've noticed certain weapons have issues occasionally with reloading automatically. Mainly exotics, Cryosthesia, Eriana's, Traveler's are the ones I have seen it the worst at. When it happens, ADS makes the screen shake semi-violently as long as you hold the trigger down. Hip-fire just has you holding your gun and not doing anything until you stop holding down the fire button. This occurs completely randomly. Shooting enemies, using the action of the two sidearms, reloading. It could happen during any of these actions or something different. It could happen consistently or it could take five minutes for this phenomenon to occur.