So me and an outfit mate tried to participate in ops tonight but enemies and mates alike would be walking through the air or not appear at all but some players would walk around normally. Really weird.

Somehow this bug only affects one character; on my bot alt, it works fine.

Validate your game files via Steam, that will discover 19 broken files. Steam fixes those and the issue is gone.

Thanks to Metabolich and Ferusvir from [RMIS] for figuring this out.