Thanks for your reply, Tim.
I repeated my test just to be certain of the users involved. I used the same user to create the course backup, create a new course and restore the backup into the new course. The user is among the site administrators.
I also repeated my quiz slot analysis and returned all the same numbers as the first time. Furthermore, spot checking several of the slots that end up pointing to different questions than the source course, in both of my restored courses, the same quiz slots ended up pointing to the same different question.