[Samba] Online Backup Fails - list index out of range

[Roy Eastwood]

In another thread on this list (https://lists.samba.org/archive/samba/2019-August/225607.html), Rowland suggested that the following
command doesn't work ie it still requests the password:

 samba-tool domain backup online --targetdir=<output-dir> --server=<DC-server> -k yes

However, I tried it out on one of my DCs and found it created the backup but failed at the end as this excerpt of the console output
shows:

root at tiger-db:~# kinit Administrator
Password for Administrator at MICROLYNX.ORG:
root at tiger-db:~# samba-tool domain backup online --targetdir=backups --server=tiger-db.microlynx.org -k yes
INFO 2019-08-29 17:03:50,319 pid:13945 /usr/lib/python3/dist-packages/samba/join.py #1549: workgroup is MICROLYNX
INFO 2019-08-29 17:03:50,320 pid:13945 /usr/lib/python3/dist-packages/samba/join.py #1552: realm is microlynx.org
Calling bare provision
...
[snip]
...
Committing SAM database
INFO 2019-08-29 17:04:06,889 pid:13945 /usr/lib/python3/dist-packages/samba/join.py #1643: Setting isSynchronized and dsServiceName
INFO 2019-08-29 17:04:07,303 pid:13945 /usr/lib/python3/dist-packages/samba/join.py #1555: Cloned domain MICROLYNX (SID
S-1-5-21-4012640977-2272627666-3977488320)
ERROR(<class 'IndexError'>): uncaught exception - list index out of range
  File "/usr/lib/python3/dist-packages/samba/netcmd/__init__.py", line 185, in _run
    return self.run(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/samba/netcmd/domain_backup.py", line 258, in run
    new_sid = get_sid_for_restore(remote_sam)
  File "/usr/lib/python3/dist-packages/samba/netcmd/domain_backup.py", line 81, in get_sid_for_restore
    rid = int(res[0].get('rIDNextRID')[0])

Is this another bug?

Thanks,

Roy