I noticed that my aim suddenly spun in the opposite direction when I ADS on an enemy and I have found how to recreate this glitch. Whilst tapping Alt + Right click + Move mouse, it will always instantly spin your view to face East every time, I have been able to recreate it multiple times and even got a friend to do it. It's just unfortunate that this glitch happens when you need to quickly turn and kill someone.
I've noticed that I can see someone sitting next to a tree at roughly 500m, then if I scope in with an ACOG or 8x they fade away behind the tree, then when un scoping they fade back in front again. I'm not cheating either.