some home video files went missing
I have 90 home videos that were initially loaded into iTunes 5+ years ago and that now show up on the Library tab within the Apple TV app. Although all 90 videos appear in the library, more than 30 are no longer playable because their m4v files somehow went missing through all the macOS upgrades over the years. Get Info for the missing videos shows the mystery path "file:///Users/Username/Movies/iMovie Library.imovielibrary/My Movie/Shared Items/XSZlzM9YRD2PUbs50ej+1g/Filename.m4v". Get Info for the videos that still work yields a much simpler path: "users/username/movies/Filename.m4v". I have searched all files on the entire disk, and the missing ones are simply not out there. What could have happened to them through macOS upgrades? Thanks for your help.
MacBook Pro 15″, macOS 11.2