OA creates the customer even if existing email is specified as login name and the following error is thrown:
The specified email address is in use. Please try another one.
Despite the error OA will create as many accounts as button 'Finish' pressed. However each one will be without staff members.
Account and staff member are created in scope of separate transactions and account's one is committed before staff member receives an exception.
Corresponding software issue #APS-44209 was submitted.
Contact your Technical Account Manager or Pooled Technical Associate Team (firstname.lastname@example.org) in order to trace the current status of #APS-44209.