Pretty sure it's just the nature of Unreal Engine. I've seen a lot of UE games over the years where they tend to be more CPU limited than other similar looking games. 120 fps minimums (at 1080p ultra) suggests they're less efficient on caching or something and so they have to pull data from RAM and that's slower. Or maybe it's something else, but I've seen a lot of games over the years where minimums don't even break 100 fps.
Yeah, it's pretty crazy because those gulf-like performance deltas are what makes it noticeable. A 1% minimum under 100FPS wouldn't be so terrible if the average FPS was, like, 120. These huge differences paint a pretty crappy picture.
The weird thing though, is that there are some very well-optimised UE4 games (Borderlands 3 comes to mind) so optimisation is possible. I wonder why some game studios just can't seem to get it right.
I know that a remake of Silent Hill 2 is coming and it uses UE4. That game was a vicious psychological assault to begin with, just imagine how bad it would be if frame stuttering was added to the experience, just to screw with your head even more.
Although...I seriously doubt that a legendary game studio as big, old, rich and proud as Konami would allow the game to be released before it was perfect. Although, for the most frightening video game in history (and it
really is), being "perfect" might not be so great of a thing for the player...