We are testing Moodle 3.7 with courses created in earlier versions of Moodle. We couldn't restore courses; the restore ended with a message about too many top level categories in context of question category.  I got this error even if I deselected the quiz when backing up.

I verified that there were multiple instances of "Top of...." in the quiz category for all courses that failed to restore. These "top of ..." categories don't appear in the older version of Moodle (3.4) but they're visible in drop down menus in 3.7. Unfortunately, they don't appear when I view the categories so I can't delete them there. I recreated courses in Moodle 3.7 and managed to get rid of the excess "top of...." categories - at least only one 'top of' category appeared in the quiz question category for the course. 

I am able to backup and restore the re-built courses if the quiz uses questions in the 'default for course' category. When I link to an external bank, for example one that's in the System category, there's a warning when I backup the course of the danger that the external components, quiz questions, may not work if the course is restored on a different site. However, when I restore the course to a different category BUT on the same site as the original, the restoration ends with the error about too many top level categories.

This is cause for concern because we have courses with slightly different content in different programs that use the same quiz questions. I was hoping those courses could link to a shared question bank. But I won't be able to restore any course that uses an external bank.

Is this a known issue? Any suggestions on what else I can try?

Thank you