Teachers appear in quiz reports when ''enrolled users who have, or have not, attempted the quiz" option selected

Create a course. Enrol a student and a non-editing teacher. Make a group 'Test group' and put both users in the group. Add a quiz, set to 'Separate groups' mode. Go to Quiz settings -> results -> Grades. Change the setting to "enrolled users who have, or have not, attempted the quiz" and show the report. Verify the student is listed and the teacher is not. Change the group selector to 'Test group' Verify the student is listed and the teacher is not. Change the group selector back to 'All groups' Change the report setting to 'users who have attempted the quiz. Verify there is not data displayed (because no-one has attempted the quiz. If you are paranoid, you could also click through the 'Grades' and 'Response' reports for the quizzes here: https://qa.moodledemo.net/course/view.php?id=2#section-9 , just to provide an added check that there are no unexpected regressions.