You may have noticed that when modifying the external e-mail address (targetaddress: Email Addresses tab > Click ‘Modify’ next to ‘External e-mail address’) in ARS MMC, the Mail-attribute gets updated accordingly. Performing the same operation in Web interface does not update Mail attribute.
This is a product defect (TF00609310).
This Product Defect (TF00609310) has been fixed in the latest available maintenance release, you can get more information from its ReleaseNotes:
Active Roles 7.0.3 - Release Notes