Our Site Builder will show an approximation of what things will look like, and it's a great way to view your changes as you are making them. However, it's important to keep in mind that this is simply a preview of the changes you are making to your site.
Since there are certain placeholders that display unique information for the individual viewing the page, those areas will show "Liquid Error: Internal" within the preview. Rest assured, that the live versions of these pages will properly pull in the correct details, such as a course or student name. See below: