No, the FAQs are still part of the Ember app. By “static page” above, I meant pages that don’t load the Ember app at all. There aren’t many of those
I ran a few quick tests, and the only way I can hit a non-Ember 404 page is if I type a bad URL in the browser by hand. If I click on a link inside Discourse that points to a 404, the rendered page is coming from Ember, and thus it’ll contain the nav controls at the bottom in DiscourseHub. I tested this by sending myself a PM with a link to an inexistent URL.
Adding the controls to the non-Ember 404 page is not simple, that code depends on Ember and device detection, so we can’t simply copy/paste it there.
When you get this 404, can you click on the logo? That should bring you to the Ember app side of things, and all should work fine from then on…