Hi Ian

This looks as though this is a course topic which doesn't have the text editor to format the content.

This was probably done by copying and pasting the heading from somewhere and there is some hidden html included with the copy.

I assume you have deleted the content and reentered it and the format is still sticking? If this is the case then you may have to create a new course topic without copying content and move this into the location you want  

Regards