So the issue isn’t the footer specifically, the content of the body is not being loaded, and then is being loaded in via javascript. This is probably being done by an app, it’s most commonly done by contnet lock apps, as they will need to hide the content of a page based off of dynamic conditions.
The body tag has an id of appstleCustomBodyMarker. So you can investigate based off that naming if you have an app that has that name.