sssd error with Samba 4.0 LDAP_PROTOCOL_ERROR

[steve]

Hi
I'm trying to pinpoint a problem with sssd. When a user logs in, his 
rfc2307 attributes _should_ be pulled from AD (not the cache), however 
instead and upon login, Samba 4.0 gives us LDAP_PROTOCOL_ERROR. It 
occurs once upon authentication and once again upon logout. The session 
goes ahead fine but without recent changes to the user in the directory 
(e.g. group membership) until the sssd cache expires.

Could you tell us what would produce the protocol error?
Cheers,
Steve