in scorm_insert_track we check if the score or completion status has been changed before triggering the scorm_update_grades.

this code:
if (strstr($element, '.score.raw') ||

was used instead of explicitly stating the scorm 1.2 and 2004 variables which both use that suffix but a slightly different prefix. The problem is that this will also trigger an update when a scorm package contains objectives which can also have a similar suffix:
cmi.objectives.n.score.raw

packages that use objectives will often contain a large number of objectives - which means on exit of the scorm package we could end up triggering a grade update at times that we shouldn't need to.