1024: Operation failed - Add Sender to Address Book

One of my users gets “1024: Operation failed” when adding a sender to his address book whose email address is in the format:

“First, Last (US)” first.last@domain.com

It must be the (US). Any help on how to make this work is much appreciated.

NB

Subject: 1024: Operation failed - Add Sender to Address Book

We have recently experienced this same issue. An email with an Alias comes in and when the person hits the “reply” button Notes truncates/changes the outgoing email from"Smith, John (PHD)" jsmith@bogus.com

Appears in notes as

“Smith, John (PHD)” jsmith@bogus.com