by Alberto Di Vita.
Hi
I've encountered some similar issues. I've done this.
1) IMPORTANT: If you have custom course fields set to UNIQUE, they must be set to NON-UNIQUE,
because the restore sometimes crashes if the value remains NULL.
It seems that moodle cannot accept a "duplicate null" in am unique custom field, but not in
all scenario: it's weird.
2) Create a new 1st level system category.
3) Create an empty course.
4) Import the course data EXCLUDING the quiz.
5) Export the test in Aiken format from the old course.
6) Rebuild the test in the new course.
If you want to use the CLI, you must disable the import of custom fields and questions.