[Samba] FSMO commands not working on 4.3.1

[George]

Hi guys!
I am currently running 4.3.1 on Debian Jessie (compiled from the
experimental repo).

Pretty much everything seems to be working fine, but the FSMO functions:

---------
root at dc2:~# samba-tool fsmo show
ERROR(<type 'exceptions.KeyError'>): uncaught exception - 'No such element'
  File "/usr/lib/python2.7/dist-packages/samba/netcmd/__init__.py", line
175, in _run
    return self.run(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/samba/netcmd/fsmo.py", line 395,
in run
    domaindnszonesMaster = get_fsmo_roleowner(samdb, domaindns_dn)
  File "/usr/lib/python2.7/dist-packages/samba/netcmd/fsmo.py", line 42, in
get_fsmo_roleowner
    master_owner = res[0]["fSMORoleOwner"][0]
---------

Transfering or seizing the roles one by one, I can see that any operation
involving the two "new" roles (domaindns and forestdns) is what actually
breaks it.

I don't think this is an upstream bug (is it?) Any ideas?

Best regards,
George