Moodle schema changes?

With a recent upgrade to Moodle 2.7, a customer of ours is reporting their CustomSQL reports are failing. For example, [this query][1] used to report gradeable items, but fails now: SELECT u.firstname AS "First", u.lastname AS "Last", c.fullname AS "Course", a.name AS "Assignment" FROM prefix_assignment_submissions AS asb JOIN prefix_assignment AS a ON a.id = asb.assignment JOIN prefix_user AS u ON u.id = asb.userid JOIN prefix_course AS c ON c.id = a.course JOIN prefix_course_modules AS cm ON c.id = cm.course WHERE asb.grade < 0 AND cm.instance = a.id AND cm.module = 1 ORDER BY c.fullname, a.name, u.lastname A quick query or two to the DB shows there are zero rows in prefix_assignment_submissions and prefix_assignment. Suggestions? [1]: https://docs.moodle.org/27/en/ad-hoc_contributed_reports#All_Ungraded_Assignments