Stutters only during cutscenes; works fine during gameplay

My cutscenes seem to stutter and freeze when playing the campaign mode. However, gameplay seems to be just fine. All UI is just fine, and my frame rate is fine too, just the cutscene itself stutters and lags. I've attached a video showing what happens, alongside my VRAM usage at the time.

Note: Turning off VSync did not help, windowed and borderless did not help, and changing graphics quality levels did not help.