If I make a backup of a course and then restore that backup into another moodle site, the questions get assigned to a wrong person. Backup file (moodle.xml) includes the following info for each question:
            <CREATEDBY>xyz</CREATEDBY>
            <MODIFIEDBY>xyz</MODIFIEDBY>
where "xyz" is the id number of the user who created or modified the question. The problem is, if you restore the backup to another moodle site, user xyz is a totally different person (!)

I suggest that if a backup is restored to another site (it can easily be detected during the restore process by comparing <ORIGINAL_WWWROOT> from the moodle xml file to the current www root), both values (CREATEDBY and MODIFIEDBY) should be set to 0 (unknown) or 1 (admin user)