When crouched + crouched lower and upper stances, aiming at the highest possible angle makes the crosshair aim higher than the actual aimpoint. When the rifle is fired the crosshair snaps back to where the barrel is pointing. I've only seen this happen with rifles.

I can see that this is a feature to enable you looking higher than you can aim. Just make the crosshair stay at the aimpoint, and let the view move freely the last bit