I have SOGo (MTN trunk) installed and am using MySQL for the authentication. The view holding the user information looks as follow:
+------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| c_uid | varchar(255) | NO | | NULL | |
| c_name | varchar(255) | NO | | NULL | |
| c_password | varchar(255) | NO | | NULL | |
| c_cn | varchar(255) | NO | | NULL | |
| mail | varchar(255) | NO | | NULL | |
+------------+--------------+------+-----+---------+-------+

c_uid, c_name, c_cn and mail are all having the same value: the users email address (aka: foo@bar.tld)

c_password has the password in plain text.

Now when I send a mail from SOGo I always get a double entry in the from header:

from: foo@bar.tld,
foo@bar.tld

Why is that? How can I avoid this issue?

My Defaults file contains:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//GNUstep//DTD plist 0.9//EN" "http://www.gnustep.org/plist-0_9.xml&quot;>
<plist version="0.9">
<dict>
<key>NSGlobalDomain</key>
<dict>
</dict>
<key>gdnc</key>
<dict>
</dict>
<key>sogod</key>
<dict>
<key>GCSFolderDebugEnabled</key>
<string>NO</string>
<key>GCSFolderStoreDebugEnabled</key>
<string>NO</string>
<key>NGUseUTF8AsURLEncoding</key>
<string>YES</string>
<key>OCSFolderInfoURL</key>
<string>mysql://mysql_user:mysql_password:3306/sysdb_sogo/sogo_folder_info</string>
<key>OCSFolderManagerSQLDebugEnabled</key>
<string>NO</string>
<key>SOGoACLsSendEMailNotifications</key>
<string>YES</string>
<key>SOGoAppointmentSendEMailNotifications</key>
<string>YES</string>
<key>SOGoAuthenticationMethod</key>
<string>LDAP</string>
<key>SOGoDayEndTime</key>
<string>18</string>
<key>SOGoDayStartTime</key>
<string>8</string>
<key>SOGoDraftsFolderName</key>
<string>Drafts</string>
<key>SOGoFirstDayOfWeek</key>
<string>1</string>
<key>SOGoFoldersSendEMailNotifications</key>
<string>YES</string>
<key>SOGoForceIMAPLoginWithEmail</key>
<string>YES</string>
<key>SOGoIMAPServer</key>
<string>localhost</string>
<key>SOGoLanguage</key>
<string>German</string>
<key>SOGoLoginModule</key>
<string>Mail</string>
<key>SOGoMailDomain</key>
<string>foo.tld</string>
<key>SOGoMailListViewColumnsOrder</key>
<array>
<string>Flagged</string>
<string>Unread</string>
<string>Attachment</string>
<string>Priority</string>
<string>Date</string>
<string>Subject</string>
<string>From</string>
<string>Size</string>
</array>
<key>SOGoMailMessageCheck</key>
<string>Every 2 minutes</string>
<key>SOGoMailSpoolPath</key>
<string>/var/tmp</string>
<key>SOGoMailingMechanism</key>
<string>smtp</string>
<key>SOGoProfileURL</key>
<string>mysql://mysql_user:mysql_password:3306/sysdb_sogo/sogo_user_profile</string>
<key>SOGoSMTPServer</key>
<string>127.0.0.1:30025</string>
<key>SOGoSentFolderName</key>
<string>Sent</string>
<key>SOGoTimeFormat</key>
<string>%H:%I</string>
<key>SOGoTimeZone</key>
<string>Europe/Zurich</string>
<key>SOGoTrashFolderName</key>
<string>Trash</string>
<key>SOGoUserSources</key>
<array>
<dict>
<key>canAuthenticate</key>
<string>YES</string>
<key>id</key>
<string>maillogin</string>
<key>isAddressBook</key>
<string>NO</string>
<key>type</key>
<string>sql</string>
<key>userPasswordAlgorithm</key>
<string>none</string>
<key>viewURL</key>
<string>mysql://mysql_user:mysql_password:3306/sysdb_sogo/sogo_view</string>
</dict>
</array>
<key>SxVMemLimit</key>
<string>384</string>
<key>WOLogFile</key>
<string>/var/log/sogo/sogod.log</string>
<key>WOMessageUseUTF8</key>
<string>YES</string>
<key>WOParsersUseUTF8</key>
<string>YES</string>
<key>WOPidFile</key>
<string>/var/run/sogod/sogod.pid</string>
<key>WOPort</key>
<string>20000</string>
<key>WOUseRelativeURLs</key>
<string>YES</string>
<key>WOWorkersCount</key>
<string>1</string>
</dict>
</dict>
</plist>

The service in Postfix is:

127.0.0.1:30025 inet n - n - - smtpd
-o content_filter=lmtp-amavis:[127.0.0.1]:10024
-o cleanup_service_name=pre-cleanup
-o smtpd_client_connection_count_limit=0
-o smtpd_client_connection_rate_limit=0
-o smtpd_client_restrictions=permit_mynetworks,reject
-o smtpd_data_restrictions=reject_unauth_pipelining
-o smtpd_delay_reject=no
-o smtpd_error_sleep_time=0
-o smtpd_hard_error_limit=1000
-o smtpd_helo_restrictions=
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o smtpd_soft_error_limit=1001
-o strict_rfc821_envelopes=no

I use a own service for SOGo because I don't know how to get SOGo to use SMTP AUTH (which I usually require for sending mail over the server).