I have checked the forum for this issue, but I don’t see it (though I’m not sure I know well enough what the issue is to know how to search for it). I am having an issue with the header on my 404 page. It doesn’t appear full width like the other headers in my site.
When I remove the header I added to the 404 content template, use page Layout to apply a full-width template to the 404 page, and use Display Rules to add the page header I designed to the 404 page, it displays a post title and featured image. That gets me halfway there though because at least the page content is full width now.