Display Name incorrectly displayed when composing email


New Email
My display name changed recently without my knowledge to a single character (e.g. k <DonaldDuck@aol.com) from the full name that I had originally typed in (e.g. DonaldDuck DonaldDuck@aol.com). When I figured this out I edited / corrected the Compose > Display Name to what it should be. However, this only corrected the AIM display name and not the Mail display name which still only displays the single original character as above.

Any ideas on how to correct this problem and get Mail to to display the correct display name?