Actually, nothing was changed and this is the same behavior as seen in Core7, errors are echoed to /tmp/backup_status.
However, I can also echo those errors to the output so one will know if there was a non fatal error.
EDIT: I really don't want to change behavior of the base tools shared between Core and dCore except where it is necessary, and this is not a dCore specific issue so I would rather leave it as is.