Hello, I encountered a strange bug while playing coop. It completely blocks off vision while ads with any holographic sights attached. (doesn't affect default iron sights).
If you're not ads you can see the square by simply looking down. (sorry for not having an image while ads, I literally deleted it by mistake on steam screenshot list while making this post.)
It also blocks the ability to pick up any stuff from the ground. (and yes, the missing arms, gloves, tattoos are also an issue)