Reply to internet address forces user to setup new contact

I have a couple clients that receive a dialog to setup new contact when responding to an email with external address. This is not a global issue as it does not happen with any other users. Any ideas? Could it be an issue with the Recent Contacts view and the “Do not automatically add contact…” in preferences?

Subject: can you please tell us the exact message they are getting?

I have never seen this problem, but the text of the message might help us to debug.

Subject: Response to internet address forces user to setup contact

Thanks for your assistance. I’ll head over to the users and get a screenshot or at least the exact message and will post back here asap.