Issue with completion in LMS

Hello-

We recently launched a Storyline course into our LMS test environment and had 3 people test it. 2 of us were able to complete the course without issue, but 1 person completed it but was not brought to the sign-off/completion certification page. Upon relaunching the course today and starting over from the beginning, it worked without issue.

Our Learning Services contact has asked us to contact Articulate Support in order to address this issue before he will move forward with moving the course to Production, because if 1 out of 3 have this issue during testing, it will likely occur for more users in the production environment.

Our completion criteria is set to complete all slides, and we do not allow users to jump from slide to slide (they must go in order). This tester who experienced the issue did make it to the very last slide and showed us the final slide, so we know that this issue did not occur because of her lack of completion.

Please let me know what could be causing this error, and what we may be able to do to solve.

Thanks,

McKenzie