I have a user with Outlook 2003 connecting to an Exchange 2007 Server. If they delete all entries for a particular user from their address list and pull from the GAL, they have one address that pops-up when they send the next mail to them. However, if they reply to an email from that user, it adds another address to their file and they are show 2 entries for the same user.
Both entires are type "EX". One will be formatted as:
/o=messaging/ou=Administrative Group/cn=Recipients/cn="user alias".
The other will look like:
/o="Exchange organization name"/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn="user alias".
The second entry is the one created after the reply.