twest Very sorry to hear about this. I know this is frustrating and stressful. Hope the manual recovery proceeds smoothly.
Question: Is the backup server still a BTRFS or EXT4 Server?
I have only had problems moving sites between servers, and/or restoring them if something happened, from sites migrated via Plesk importer. There were issue with how mysql users were created AND ftp users could not be transferred or restored.
After migration from Plesk, we had to remove imported db users, and manually create new ones very similar to what you are doing, or else we could not move sites between servers, and restoration of a site would essentially fail the same exact way you describe.
We alsoI had ongoing problems moving sites with old Plesk ftp users, and we had to finally (3 days prior to move to v.12) remove every single FTP user via commands provided by Adam, which was painful. We have since had the FTPS cert bug... and have to tell users to just "accept the self-signed certificate"
It does make me wonder if you are running into something similar, particularly with the DB user(s).
