MediaWiki version: 1.35.0-wmf.4
Call to a member function getModel() on null
Users are consistently unable to edit some pages on the site.
When they try, the server responds with an HTTP 500 Internal Server Error due to the PHP runtime encountering a fatal error from MediaWiki.
This seems to affect some of the same pages that cannot even be viewed, as reported in T203075. However the exception is different so reporting separately for now.