Third party auth with a user that colides same username and different email

I have developed some features for my company on edx platform third part authentication in the recents 2 months, but today, I found a problem testing the pipeline functionality, and i want to know if is a real bug or a desired behavior. When in the database are a user with a specific username, and you try to do 3rd part auth, with a SSO and the sso give the same username but different email. This test common/djangoapps/third_party_auth/tests/specs/ specifies that a new username should be generated for that user, and then redirect to /login, but the truth is, in that case, when the new user email is different to the old, the 3rd part auth pipeline redirects to /register.

So, i want to discuss that because i don’t know where is the problem. ¿is in the test case? or ¿login pipeline?