Emma, we face this same issue in Moodle 2.5.5+. Issue exists with both SCORM packages and Lesson activities. I hope someone else has more information to share.
Courses and course formats
The problem of Display of Course Completion
Αυτή η συζήτηση κλειδώθηκε κι έτσι δεν μπορείτε να απαντήσετε σε αυτή.