Thanks John!
No, it's not supposed to work like that... A few ideas:
1. Go into Email Auto Linking and make sure your email address is NOT checked. This will link everything you send or receive. So, that could be causing it. You want to link all the other boys and girls, not yours.
2. Are the emails that are duplicated between you and the other user? Or, were they copied on the email? That could create duplicates...
3. I'm assuming your two users have different email addresses...
4. If it's just one contact's record that's doing it, then I'm leaning towards you both being copied on the email thread.
Hope that helps... If not, see if you can find something that's common to both users and that one contact.
Take care,
Lon