General developer forum

I don't think cron renumber courses. course-ids remain the same. Deleted courses-ids return "Can not find data record in database table course."
if $course not set, try  if (!isset($courses)) {...}.
get_course if id not empty return $DB->get_record('course', array('id' => $courseid), '*', MUST_EXIST); 
and that trows an dml_missing_record_exception.