UrBackup saved duplicated files without changes

How to configure UrBackup to only save one copy of original
and another copy if they are changes. Now, it is saving multiple copies

Regards, Benjamin.

How do you find that urbackup is saving multiple copies unchanged?
By looking into backups ?

Note, that there are hardlinks to unchanged files in backup directory.

Yes, I have detected by searching for certain files on the UrBackup server disk.