We are using moodle 3.8.3 LAE version, PHP 7.2.31 and MySQL 5.7.30
We are running a summer course in this instance of Moodle and several users reported the error message below.
The trigger for this error is using the forums. If you submit a new forum topic, go back and edit that topic and then save, this error will appear. You have to log out/in to clear the error.
Also, we have anonymous posts to forums turned on. We turned it off - default - but the problem still happens.
Exception - Argument 34 passed to mod_forum\local\entities\forum::__construct() must be of the type integer, null given, called in [dirroot]/mod/forum/classes/local/factories/entity.php on line 108