You're right Brian, - after shutting down slurmdbd on the cloned DB node, sshare still shows the dummy user !!
BUT `mysqlshow -p --status <Slurm-DB>` shows a different creation date for the cloned DB. - 'localhost' is already set for the SlurmtctldHost and AccountingStorageHost (slurm.conf) and DbdHost (slurmdbd.conf), as local files into cloned node I guess I've changed these values, after shutting down slurmd daemon (at the very beginning) on Node. - Original slurm.conf file is a NFS shared file for all the other nodes, and the head machine - slurmdbd.conf is a specific local file for Head machine too. - BackupHost parameter is not present in slurm.conf (on node, neither on Head) 😞