Remove_unknown command deletes all backups from DB

I have Urbackup 2.4.15 running on Debian with ZFS.
I setup ZFS backup folders as says in documentation. Backups are working correctly. One of the computers has some errors and I´d like to delete all the backups for this computer. After delete de computer from Urbackup GUI, the files remains in the filesystem… so I tried to do a remove_unknown command… After that, all backups were deleted from the Urbackup DB (not from the filesystem itself).
Is there any problem with remove_unknown command with ZFS in 2.4.15 ?

Thank you