Course will not complete

I created a course that learners take by initially selecting their role in the organization. There is a variable for each role set to "false". When they select the radio button for their role, the variable for their role turns "true".  The logic in the course creates a path of slides (each containing a ~30 second instructional MP4 video) that the learner will go through based on their role. The problem is that just before jumping to the closing slide, the "wheel of death" appears (Storyline is spinning trying to think of what to do next). The logic in the second to last slide for each role tells the course to "Jump to Closing Slide when the user clicks Next if the "learners chosen role" = value true." It seems to happen more with 3 specific roles, but not always. There are people in those roles that do complete the course. But often, a learner gets the wheel of death and it never stops turning. They are stuck at that spot. Have you seen this happen where some are able to get through and others are not? What could be causing this? WE use Cornerstone for our LMS.