Why does Drupal Commerce change an original username to the full billing name?
I've noticed that if a customer with username of, say 'jd' comes to a Drupal Commerce sites and purchases an item with his credit card, entering 'John Doe' as his full billing name, that Drupal Commerce will from that point on, consider and list his username as 'John Doe'. If one looks at the list of users (/admin/people), his username will be listed as 'John Doe' but if you edit his account, his username then appears as 'jd'.
Beside being non-intuitive, this is proving to be very problematic because the 'Add an Order' feature will always ask for their original username but if you look in the /admin/people list, you won't find it. So how can site managers find the original? This is bizarre and confusing behaviour.
How can I change this to prevent the system from swapping names for the same account, or at least how can I access the original username?
I'd appreciate any help or insight into this as it's becoming a compounding problem.