Editing First Name in CiviCRM profile group updates database incorrectly

Assume we have the following 2 groups in the CiviCRM Profile

1 - CiviCRM Name and Address
First Name

2 - Group 1
First Name

• Now for the drupal admin user change the profile to have firstname/lastname as Foo Bar

• Search Contacts
  Listing shows Foo Bar

• Edit myaccount for drupal admin user.

• goto Group1 tab
• change first name from 'foo' to 'abc'.

• Search Contacts

• notice the contact now has only first name of 'abc' and no last name.