The URLs of manuals restored from backups differ from the original manuals.
Restoring from a backup involves creating a new manual based on the past backup data. Existing manuals are not overwritten by the backup data.
If you do not want to change the manual URL, you can use the clipboard function to reflect the content of the manual restored from the backup to the existing manual.
Related:
Restore manual from backup (Web Browser)
https://teachme.jp/8/manuals/9917832
Use clipboard function (Web Browser)
https://teachme.jp/8/manuals/11054649