samba - Aug 2013 - Samba 4.0.5 User who has same password then Administrator authenticated as Administrator.

Hi list!

I use samba 4.0.5 as ADDC and I have more shares. Everthing great but I 
have some share premission problem.
There are some users who have same password then Administrator, they 
authenticated as Administrator on shares.
These users don't have premission to these shares.

For example:

Administrator's pass is 123uberpass
user1's pass is 123uberpass too

And logon to win2k8r2(simple domain member client) (with RDP) with 
user1, and i try open a share, what has premission only for 
Administrator, it SUCCES. And syslog show:
"mydc smbd_audit: MYDOMAIN\Administrator|192.168.1.249|open|ok|r|." 
(Administrator instead of user1!)
Then I change password for user1 to 123otherpass, and i try open a 
share, what has premission only for Administrator, it DENIED. (this is good)

When I rechange pass to same then Admin's pass for user1, shares access 
SUCCESS again. And so on...

What could be the problem?

Thanks for replyes, and excuse me for my bad English.

Regards.