Thanks for this bug report. I have the same problem (…two years later). Some video cutscenes are literally unwatchable, like they were extremely poorly encoded to an obscenely tiny file size. The end of “Blood, Ice & Steel”, Act 2, “A Father’s Sacrifice” (final video of act) to be specific, is a complete mess like your screenshot. But I’ve noticed strong artifacts in other videos, even the intro before main menu. No problems in-game whatsoever, just the videos, which I assume are videos not game engine. I don’t know what could cause this other than terrible video encoding (ultra-low settings, compression artifacts).
Build: 100.14.7908.0
Platform: Xbox (App, PC)
OS: Windows 11 Pro (22H2)
Hardware: AMD Radeon 6600 XT (AMD Software 23.3.1)
Screens: Gallery (Imgur)
Update: Fixed! Thanks to McLerristarr. In graphics settings, change anti-aliasing to FXAA or none (do not use temporal).