python-social-auth
will create a unique username for each user in case of a collision, the default resolving method is to append a hash to the end of the username, so it will became joed41d8cd98f00...
, the method that takes care of that is here https://github.com/omab/python-social-auth/blob/master/social/pipeline/user.py#L9-L53.
You can override the default behavior by replacing that method in the pipeline (or adding another after that one which applies some transformation to the generated username).