I will preface this by saying that I am not by any means a savvy Scrivener user, so this can very well be a bug between the chair and the keyboard and if so, I apologize.
I’m using the automatically generated Table of Contents and no matter what settings I tick or untick and whatever I do, it always generates the heading twice.
To verify, does the text show up in the HTML itself, when opened in an editor like Sigil or Calibre? That kind of looks to me like a book reader adding a “page header”.
Whatever the case, I do not get this result when compiling to ePub3, and viewing the result in the Calibre ebook viewer or Sigil.
The screenshots are from Calibre and it’s compiled to epub 3
But it doesn’t show up in epub 2