No author problem for svn server

Hi there,
I'm recently encounting a weird problem, not sure when it started, my svn server doesn't log the author when committing. We are a team, but it forgets most of the members, only one person exception, there's no different between this person and others. though every one is able to access and commit as usual, My svn server authenticates against LDAP and no anonymous access allowed. here is the config and log:
--------------<VirtualHost *:80>

  ServerAdmin svnadmin_at_abc.com

  DocumentRoot /var/www/svn

  ServerName svn.abc.com

  ErrorLog logs/svn.int.abc.com-error_log

  CustomLog logs/svn.int.abc.com-access_log common

  <IfModule mod_authz_ldap.c>

    <Location /svn>

      DAV svn

      SVNParentPath /var/www/svn

      SVNReposName "Subversion Repository"

      # SSLRequireSSL

      AuthBasicProvider ldap

      AuthType Basic

      AuthzLDAPAuthoritative on

      AuthName "Authorization Realm"

      AuthLDAPURL "ldaps://ldap.abc.com/ou=people,dc=abc,dc=com?uid?sub?(objectClass=*)" NONE

      AuthLDAPBindDN uid=svnadmin,ou=people,dc=abc,dc=com

      AuthLDAPBindPassword RjOmm4JIM8VNuecbw7xZ       <Limit GET PROPFIND OPTIONS REPORT>

        Require valid-user

        require ldap-group cn=svnusers,ou=groups,dc=abc,dc=com

        AuthLDAPGroupAttribute memberUid

        AuthLDAPGroupAttributeIsDN off

      </Limit>

    </Location>

  </IfModule>

</VirtualHost>

--------------------
$ svn log...r12 | (no author) | 2015-02-12 10:33:15 +0800...
------------
Do I forget anything?
Jeff
Received on 2015-03-20 16:56:48 CET