CSRF-verification failed when trying to log in
Users occasionally get a "CSRF-verification failed" error when trying to log in. This seems to be related to this explainer in Django's docs.
My hypothesis is that users somehow get logged out and brought to the login page with a now invalid CSRF token in the login form. Trying to login with this invalid token causes the error. To be able to log in again, the user has to reload the page completely.