django-python3-ldap authentication
From the documentation:

When a user attempts to authenticate, a connection is made to the LDAP
  server, and the application attempts to bind using the provided
  username and password. If the bind attempt is successful, the user
  details are loaded from the LDAP server and saved in a local Django
  User model. The local model is only created once, and the details will
  be kept updated with the LDAP record details on every login.

It authenticates by binding each time, and updates the information from LDAP (as you have it configured) each time. The Django user won't be removed from Django's user table if removed from LDAP; if you set multiple auth backends to also using the Django default auth, the user should be able to login (perhaps after a password reset) if removed from LDAP. If you look in your auth_user table you will noticed users using Django auth have their passwords hashed with pbkdf2_sha256, and the LDAP users passwords do not.
I am using django-python3-ldap for LDAP authentication in Django. This works completely fine but whenever an LDAP user is (successfully) authenticated the user details are stored in the local Django database (auth_user table). 
My question now is when the same 
(LDAP) user tries to authenticate next time, the user will be authenticated by LDAP or by the default Django authentication (since the user details are now stored in the local Django database)?
If the user is authenticated using local Django database then the user can still able to get access even after the user is removed from the LDAP server? This is a real concern for me?. 
If this is the case is there a way, so that the LDAP user details is removed from the database (auth_user table) everytime the user is logged out and created every time the user is logged in?. Any help in the right direction is highly appreciated. Thank you for your valuable inputs.