The QUIZ activity, created before 4.3, that had random questions from a top category that has ZERO questions but with subcategories that have some questions can no longer be launched in MOODLE version 4.3

The error displayed is: There are not enough questions in category 1234 to create the question Random question (.....).

The old JSON format {"questioncategoryid":1234,"includingsubcategories":1} from field mdl_question_set_references.filterconditions is not processed correctly in some cases.

The second bug: the link "show all questions" is missing from the box for adding questions to the quiz, no matter which filters are applied. A maximum of 20 questions (maybe hardcoded?) can be displayed. Furthermore, the filter is lost/reset after moving to another page in the paginator.

The filter introduced more problems than it solved. It is impossible to find out graphically if the filter is applied or not...