Ive got the same problem. I tried changeing few video options it fix it for 2-3 mins then textures gets ugly again...I can't play

I found out that many time it happen when you try to relog too fast on the same server ... I might have been Lucky sometime but happened often to me aswell... but not everytime trying to reproduce that event to have better knowledge about that situation

I was unable to reproduce the one crawling Under those steps of apartments
I'll work on the cheminey one to send you a video asap

https://www.youtube.com/watch?v=s4a4p4FInIg
Found that on youtube to show you some of these glitches

when throwing a flashbang or a grenade you can't move wich is kinda annoying