Screen flashing in crypt

Bug Report ID: #4027564605

While doing endgame waitpoint in crypt, I've noticed that there's probably some problem with textures in 'Crypt' map. In most of said location, screen keeps flashing.

I have recorded what can be seen on screen, however I do not see any option to attach files here. Please let me know if you need any proof to be attached.

also got this issue in crypt during delirium