[Samba] trust relationship - a bit of a puzzle

[lejeczek]

hi all sambians

A bit of a puzzle my samba turned into, I hope you can help.
I've had 3.6.x for many years and many Win 7 (also XP in old days)
clients until last Sunday (I think) when I updated samba.
Just two win7 I get infamous = trust relationship between this
workstation ...
There rest of win7s are fine.
Nothing really changed in terms of configurations, not on the server
nor on the clients.
I've removed failing clients and then rejoined yet! I still get the
error and cannot login to the_domain\user.

Only two thing I can see may differentiate these two from the rest.
Both these two clients are on a subnet different from the rest that
works fine.
Second thing is both have not had windows updates installed in quite a
long time.

But the subnet itself seems fine, for if I login to local\user I get
name resolution via wins and I was able to rejoin these clients, as
said earlier.

In samba log I see:

[2016/04/25 14:31:18.688902,  0]
rpc_server/netlogon/srv_netlog_nt.c:976(_netr_ServerAuthenticate3)
  _netr_ServerAuthenticate3: netlogon_creds_server_check failed.
Rejecting auth request from client WORK16 machine account WORK16$
[2016/04/25 14:31:18.698578,  1]
rpc_server/srv_pipe.c:1845(api_pipe_request)
  srv_pipe_check_verification_trailer: failed
[2016/04/25 14:31:29.003200,  1] smbd/process.c:457(receive_smb_talloc)
  receive_smb_raw_talloc failed for client 192.168.2.81 read error =
NT_STATUS_CONNECTION_RESET.
  receive_smb_raw_talloc failed for client 192.168.2.81 read error =
NT_STATUS_CONNECTION_RESET.

would you have suggestions as how to start troubleshooting this?
many thanks.
L