Observed on a 19.3 instance. I'm not entirely sure how to reproduce.
1. Create assessment with due date and retract date (in next 5-10 minutes). Late Submissions Accepted -> Yes
2. Wait 10 minutes for the times to pass
3. Modify published assessment to Late Submissions Accepted -> No. Set due date 2 hours in the future
4. Take assessment as student
5. Wait 5 minutes for the auto-save to fire
Expected behavior: no warning displayed to student about "You have 5 minutes and 0 seconds left"
Incorrect behavior: warning displayed to student because of that old retract date.