[Samba] Some types of GPOs doesn't work when applied to a specific OU

[FM]

Hi Guys!

I've been testing Zentyal for some time and I find an odd situation.

There are some kind of gpo settings that are not applied when the GPO is
linked into an OU.

Example: setting a wallpaper with "administrative templates" or creating a
folder via gpo.

Other types works everywhere. Example: Computer Configuration - >
Preferences -> Windows Settings -> Shortcuts

Any explanation?

The very same GPO when applied to the root of the domain works.

When I run

 sudo samba-tool gpo aclcheck


params.c:pm_process() - Processing configuration file
"/etc/samba/shares.conf"
ldb_wrap open of secrets.ldb
GENSEC backend 'gssapi_spnego' registered
GENSEC backend 'gssapi_krb5' registered
GENSEC backend 'gssapi_krb5_sasl' registered
GENSEC backend 'schannel' registered
GENSEC backend 'spnego' registered
GENSEC backend 'ntlmssp' registered
GENSEC backend 'krb5' registered
GENSEC backend 'fake_gssapi_krb5' registered
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/gpo.py", line 1150,
in run
    ds_sd_ndr = m['nTSecurityDescriptor'][0]

Don't know if it's related...
Hints?

Samba 4.1.17