Banner Issue - How to disable or only show once?

The banner continues to overlay content, and it would be better to either disable, show once, or only show when at top of page (my choice).

Is this a theme or a Pressbooks feature?

Here is a description of the issue by a Pressbooks author and enduser:
“the internal links that take readers to a specific point on a page now take them to content hidden under the header”

Please advise on how to resolve this issue.

Fixed in