Drupal accounts created by profile in contribution page erroneously associated with Org contact

I have a profile for individual contact info that I include on a contribution page that has 'I am contributing on behalf of an organization' selected.

If the user enters the same email for both the organization and the individual contact info, the CMS account that gets created by that profile is sometimes associated with the organization instead of the individual.

Synchronize Users to Contacts under Administer CiviCRM seems to demonstrate the same problem.