When I backup or restore a course it ends with the error message:

"Did you remember to make the first column unique in your call to get records. Duplicate value stamp version "

When I restore the course in another moodle installation of 3.5.2 it works fine.

It seems that only certain quizzes/questions create the issue because an earlier version of the course with half the number of quizzes worked fine.

To reproduce: restore the course in moodle 3.5.2