Another weird item...
The following screenshot shows thumbnails for large .mov files with iCloud Drive on iOS, but these files were uploaded directly to Drive with the iOS app and then these files were deleted from my camera roll. I reset my phone removing EVERYTHING and restored through the latest iCloud backup NOT iTunes. These large files obviously have thumbnails.
I'm wondering if this issue has to do with how files are added to iCloud Drive. The files that have NO thumbnail were synced from the Windows 10 iCloud app and the files that have thumbnails were uploaded directly from iOS.
