Only the below listed format are supported for Video in lightroom
"Working with video in the Library module of Lightroom offers some simple tools for previewing, setting poster frames, and creating stills from frames that can be exported to the Develop module. Lightroom imports many common digital video files from digital still cameras, including AVI, MOV, MP4, and AVCHD."
Simply not a supported format:
Lightroom imports AVI, MOV, MP4, and other digital video files from digital still cameras. For more information, see Work with video in Lightroom.
Do I understand you to say that it is "simply not a supported format"? Why can others using Lightroom see theirs but I can't see mine?
By the way it can see .MOV files but I assume it is the Prores codec that is the problem.