[Samba] Repadmin fails when querying Samba server 4.7.6

[Ing. Claudio Nicora]

I'm trying to fix a replication error that occurs between Win2008R2 
(srvwin) and Samba 4.7.6 DCs (srvsamba).
Event viewer on Win2008R2 server reports that synchronization failed on 
a specific Computer object because of schema version misalignment 
between servers.

I've then used repadmin to compare failing object on the two servers.
Querying the windows server works but it fails querying the Samba server

*************************************
C:\Windows\system32>repadmin /showobjmeta srvwin 
"CN=MYPC,CN=Computers,DC=SAMDOM,DC=LOCAL"

30 entries.
Loc.USN                           Originating DSA  Org.USN 
Org.Time/Date        Ver Attribute
=======                           =============== ========= 
=============        === =========
  146459      edecb709-eff3-45fc-8cbd-6760e0045ca3     10595 2018-07-08 
23:16:29    1 objectClass
... lot of other rows ...
  146477      edecb709-eff3-45fc-8cbd-6760e0045ca3     10598 2018-07-08 
23:17:52    1 msDS-SupportedEncryptionTypes
0 entries.
Type    Attribute     Last Mod Time Originating DSA  Loc.USN Org.USN Ver
======= ============  ============= ================= ======= ======= ===
         Distinguished Name
         =============================
*************************************
C:\Windows\system32>repadmin /showobjmeta srvsamba 
"CN=MYPC,CN=Computers,DC=SAMDOM,DC=LOCAL"
DsReplicaGetInfo() failed with status 1359 (0x54f):
     An internal error occurred.
*************************************

This is the log capturedon samba serverwhen running repadmin:

[2018/07/09 22:36:18.056211,  3] 
../lib/ldb-samba/ldb_wrap.c:326(ldb_wrap_connect)
   ldb_wrap open of secrets.ldb
[2018/07/09 22:36:18.084253,  3] 
../source4/smbd/service_stream.c:65(stream_terminate_connection)
   Terminating connection - 'ldapsrv_call_wait_done: call->wait_recv() - 
NT_STATUS_LOCAL_DISCONNECT'
[2018/07/09 22:36:18.084815,  2] 
../source4/smbd/process_standard.c:473(standard_terminate)
   standard_terminate: reason[ldapsrv_call_wait_done: call->wait_recv() 
- NT_STATUS_LOCAL_DISCONNECT]
[2018/07/09 22:36:18.091409,  3] 
../lib/ldb-samba/ldb_wrap.c:326(ldb_wrap_connect)
   ldb_wrap open of secrets.ldb
[2018/07/09 22:36:18.093903,  2] 
../source4/smbd/process_standard.c:157(standard_child_pipe_handler)
   Child 13770 () exited with status 0
[2018/07/09 22:36:18.103075,  3] 
../source4/rpc_server/drsuapi/dcesrv_drsuapi.c:89(dcesrv_drsuapi_DsBind)
   ../source4/rpc_server/drsuapi/dcesrv_drsuapi.c:89: doing DsBind with 
system_session
   ../source4/dsdb/kcc/kcc_drs_replica_info.c:160: Failed search for the 
object DN under edecb709-eff3-45fc-8cbd-6760e0045ca3 whose invocationId 
is 
CN=Configuration,DC=SAMDOM,DC=LOCALkccdrs_replica_get_info_obj_metadata2() 
called
[2018/07/09 22:36:18.106306,  0] 
../source4/dsdb/kcc/kcc_drs_replica_info.c:228(kccdrs_replica_get_info_obj_metadata2)
   attribute_id = 0, attribute_name: objectClass
[2018/07/09 22:36:18.106761,  0] 
../source4/dsdb/kcc/kcc_drs_replica_info.c:160(get_dn_from_invocation_id)
[2018/07/09 22:36:18.119609,  3] 
../source4/smbd/service_stream.c:65(stream_terminate_connection)
   Terminating connection - 'dcesrv: NT_STATUS_CONNECTION_RESET'
[2018/07/09 22:36:18.119888,  3] 
../source4/smbd/process_single.c:114(single_terminate)
   single_terminate: reason[dcesrv: NT_STATUS_CONNECTION_RESET]
[2018/07/09 22:36:18.120038,  3] 
../source4/smbd/service_stream.c:65(stream_terminate_connection)
   Terminating connection - 'dcesrv: NT_STATUS_CONNECTION_RESET'
[2018/07/09 22:36:18.120245,  3] 
../source4/smbd/process_single.c:114(single_terminate)
   single_terminate: reason[dcesrv: NT_STATUS_CONNECTION_RESET]


Is this a bug?
How can I fix it?