These items are 'other course recommendations for courses with at least one department in common with this course' (as defined under Academics > Scheduling > Requests and Schedules > Departments & Courses).

Removing courses from sharing common departments ensures that teachers will only see their own recommendations.

Alternatively, adding all courses to a unified department will ensure teachers see all other course requests for each student in their current class.
When adding a new department, after all intended courses have the new department added, it is recommended to ensure that the new department has settings of:
  1. 'Publish to front end' unchecked
  2. 'Mark as inactive' checked
It is not necessary for teachers to be a member of a department (via Employment settings) for this to be effective.

For more information on faculty recommendations, please see the Faculty Course Recommendations & Requests Help Topic.