This could be caused by invalid HTML within the Department Description.

To strip out the invalid HTML navigate to:
  1. Core > School > Departments & Courses
  2. Find the Department Name
  3. Click the Pencil Icon next to the Department Name
  4. Click HMTL​ 
User-added image

      5. In the HTML remove any unnecessary code (you can insert spaces manually by pressing Enter.)
      6. Click Update
      7. Save & Close the Edit Department Window