First, check the style in onMessage on the curriculum detail page and verify that the style applied is functioning correctly. 

If it is, next, check the HTML in the course description in Core, if the description was pasted from another location, it may have carried over extra HTML.

To remove the extra HTML:
  1. Go to Core > School > Departments & Courses
  2. Select a Department
  3. Select Edit across from a Course
  4. Select the HTML icon In the Description field
  5. Remove the extra html code
  6. Click Update
  7. Click Save & Close
It is recommended to copy and paste in plain text, using the Plain Text icon in the course description 
 User-added image