Actual: If you assign more than one role to user where those roles are all "Course Managers" then the user is listed twice in the course description.
Expected: Each user should only be displayed once. Only the name of the most senior role assigned to the user should be displayed.
The admin page for this (admin/settings.php?section=coursemanager) says:
"This setting allows you to control who appears on the course description. Users need to have at least one of these roles in a course to be shown on the course description for that course."
This text is inconsistent with the current result as having more than one role lists you multiple times.