The cinematic cutscenes volume is being lowered too much by the Master Volume slider.
At 100% Master Volume the cutscene volume is level with the rest of the game sounds, but as Master Volume lowers, the cutscene volume is reduced twice as much as all other sounds.
At 25% Master Volume, the cutscenes are barely audible compared to other sounds.
All my other volume sliders are at default (including Environment Volume at 100%).