Summary:

I have found that if date restrictions are set for a quiz and a user attempted the quiz within that time period, once the 'available until' date/time is reached, the quiz will display 'Not attempted' on the course page (only when 'Collapsed Topics' course format is used). 

Steps to replicate:

1. Enrol a test student in a course
2. Add an activity>Quiz
3. Scroll down the settings and under 'Restrict access' add a date/time restriction where start = current date/time, end = 5 minutes from now. Ensure the eye is open for both restrictions (so that the quiz will be visible but greyed out on the course page)
4. Save and display
5. Go to 'Edit quiz' and add a simple true/false question
6. Log in as the student and attempt the quiz
7. Go back to the course page and observe the quiz activity
8. Wait 5 minutes then refresh and observe the quiz activity again

Observed behaviour:

When outside of the restrict access date/time range, the student will see 'not attempted' underneath the quiz activity on the course page even though they have attempted it.

Expected behaviour:

Student will see 'attempted' regardless of whether they are outside of the date restriction or not.