Does your Captivate have an actual score? If not, it cannot really say Passed. What do the reports show? What score is being pushed? If you have no quizzing elements, Learning Objects does a better job than other grades settings--it assigns a 1 (complete) or a 0 (not complete).
If you do have quizzing elements in your package (not using Learning Objects), make sure what you expect to be passing matches what Captivate settings actually say--there are two areas in Captivate to pay attention to:
First: You have to enable reporting. You have to tell Captivate you use Moodle. You are better off publishing in SCORM 1.2 as Moodle is not 2004 compliant. 2004 mods will run but may not behave as expected. And sometimes it does not report. You choose if you use slide views or a quiz. If you choose quiz but there are no questions, it will publish but may not actually mark completed/passed properly. If you choose both and there are no questions, it may not mark completed. If you choose 100% slide views and there are any slides the user might skip (including results pages or an end page with help stuff or something), it will not mark completed. And...do you include interaction data? This can help track.
The default is generally 80%. If you have a quiz, you have to make sure your passing percentage is consistent with what you actually expect. Grade to pass in Moodle (if used) should recognize Captivate scoring, which is weird. Captivate tends to automatically assign 10 points per graded question. 28 questions=280 pt. Multi-answer questions do get partial credit. If the student does not get exactly 80%, they don't get passing, 79.96%, nope, did not pass, no rounding but in Moodle, the score might look like a pass. Captivate is stupid complicated. The more stuff you put in it, the more room you have for weird behavior.