On course restore as a new course, the new default for course question category is left in the original course

I pinpoint another problem when working on restoring a course into a new course.(working on MDL-33586)
I just put a simple quiz with 2 questions in a new course.
I did some attempts.
backup the course and restore it as a new course in the same moodle installation.
Things seem Ok with the exception that the new questions created in the process where put in a new category which is OK.
However the new category was in the original course, NOT in the new course.
I used last $version = 2012060100