Hi.
I assume this is because of the user management of cryptomator.
(https://community.cryptomator.org/t/cryptomator-on-windows-accessing-your-vault-with-admin-priviliges)
I am using Personal Backup to do my backups into my vaults without any problems, regardleff if using WebDAV or Dokany.
Offtopic: I am using this tool also to sync the encrypted files to my own Website Hoster via FTP for use as WebDAV storage)