This is caused by changing the block associated with a course under Set Section Information and then Generating Student Schedules without clearing out existing enrollments. Once the correct blocks have been tied to the course this can be resolved by navigating to:
  1. Navigate to Academics > Scheduling > Requests and Schedules
  2. Under Student Schedules click More Actions and select clear student schedules
  3. Return to the Schedule Maker Main Menu
  4. Click Generate Student schedule to generate new schedules