Graphics degradation in cutscenes

https://preview.redd.it/5r5xkfv5nvfg1.png?width=3840&format=png&auto=webp&s=ce7d6e0c0da2b81e387083ae7357a923c82218b2

https://preview.redd.it/hdy9ydv5nvfg1.png?width=3840&format=png&auto=webp&s=dd7d0e4177b5b2504651b49853f6fc68f52f9e3d

I'm playing in 4K quality, everything is on ultra, but when the cutscenes start, the graphics seem to drop to 1080. Why does this happen?