The student in question does not have the "Override" box checked. But I think I may have found a workaround. It seems the issue is trying to get Moodle to "re-calculate" the grades in the grade book. I checked the grade "override" box for the student and saved. This caused Moodle to re-calculate. I went back and removed the check on override, saved, and Moodle re-calculated bringing the student's assignment grade into the grade book. It is a mystery why Moodle wouldn't record the grade in the grade book for the student.