I have found a very critical bug, when you restore course with users (and they have completed quiz on the course) the quiz "started on" and "completed" dates are changed to the future if the course start date during the restore is set to future also.
How to repeat;
1. Make a course and set "course start date" to today f.ex 14.11.2017
2. Add a quiz and complete it with a student
3. Open the quiz attempts-page and check that the "started on" and "completed on" are correct.
4. Make a backup of this course and Include enrolled users
5. Restore the course as a new and on the page "4. Schema" set date to future f.ex. 30.12.2017
6. Open the quiz attempts and notice that "started on" and "completed on" are now 1.12.2017
So it seems that the student have made Quiz in future so this is a very serious bug in Moodle 3.3.2 and 3.18