samba - May 2016 - winbindd: sid_to_name: failed to lookup sids: STATUS_SOME_UNMAPPED

Hello,

I move the winbind log to level 2 and now I can see this kind of message :

  winbindd[10790]:   sid_to_name: failed to lookup sids: 
STATUS_SOME_UNMAPPED

I made a search with google and I found a file called winbindd_rpc.c 
with this rem :

/* see if we have a real error (and yes the
            STATUS_SOME_UNMAPPED is the one returned from 2k)

Could somebody tell me more about this error? ( that seems not blocking 
the dyndns update by dhcpd )

Thanks a lot!

Sam