Incremental file backup client goes offline behaviour

From UrBackup - Server administration manual

Under 6 (backup process) - 6.1 (file backup):
Second last point is this: If the client goes offline during the backup and the backup is incremental the server continues creating hard links to files in the previous backup but does not try to download files again

Can this behaviour be changed? If client goes offline can it be seen as a failed run and retry?
Also if client goes offline and server just hard links rest of files, is an alert sent out when this occurs? If not how can one know this situation has occurred?

Thanks.