There is a known issue that occurs when attempting a full restore of files to a user when the same files already exist in a different folder (within OneDrive).
The Restoration will be shown as successful, but no files will be transferred into the designated folder on OneDrive. The files will still be stored and accessible in the original (different) folder so no data is lost, and this issue also ensures that the user does not have duplicates of the same file.
Please note that this issue occurs where the title and content of the files are identical to the existing files. If the title has been changed (or a change to the file has been saved), a copy of the file will be transferred to the designated folder (and the existing file will remain in it's original folder).