Quicktime, Finder, and FinalCut Pro not Playing 120FPS videos

I am a wedding filmmaker and sometimes shoot some things in 120FPS to slow down in post. I just imported some files and found that Quicktime won't show video, but there's audio. It's like it tried to automatically turn it into slow-mo as iPhones do with the adjustable bar for where you want the slow-mo. Finder won't even play the preview video or load a thumbnail. FinalCut Pro won't play the video either, just the audio. I know there is video and it's not just corrupt, because it plays like usual on my OneDrive.

Any information would be greatly appreciated!