mariabackup --backup --stream=xbstream - will create incomplete backups that are not restorable

When running mariabackup --backup --stream=xbstream, the process will incorrectly report that a backup has completely successfully although the backup config and/or the xtrabackup info files will be missing from the backup.

backup_copy.backup_finish line 1376 will return false if either the backup config or the xtrabackup info files are not written to the backup.
The returned state of this method is not handled in xtrabackup.stage_end (line 5211) and this method always returns TRUE, indicating that the backup completed successfully

Restoration of backups without either the backup config (backup-my.cnf) or the xtrabackup info (xtrabackup_info) files, will fail and the backup is un-recoverable.

I am unable to provide the steps to reproduce backup files without these config or xtrabackup info files.