Version:            (using KDE 4.4.0)
Installed from:    Ubuntu Packages

Steps to reproduce:

1. Create a new contact group, name "test".
2. Add some contacts to this group.
3. Compose a new email.
4. Type "test" into the "To" text field. A drop down box appears and shows your previous created contact group.
5. Select this group.
6. Send the email.
7. Open the sent email.
8. The receivers email is now "test@[your hostname]" which will fail. I expected the list of containing contacts.