Extra text being added to templates in popup windows

When I add templates to my pop ups, I get weird text added to the display. See in the image below where “/n” is added. What can I do to get rid of that?

Have you HTML in your template? If so, try removing all visible linebreaks and add
instead.

You can always inspect the element Ctrl+Shift+I

If you put that template on a basic page - do you get different results? 

Hey guys - I only get it in popups and no linebreak issues