generic-logos is missing topbar-bg and sidebar-bg image files - filed that as https://bugzilla.redhat.com/show_bug.cgi?id=1252252 . It seems that when the background image is missing, though, the contents of the top bar aren't rendered properly at all. It just shows as a flat blue block - none of the intended text or buttons are visible. They are *present* - if you know where the buttons are you can click them, or you can activate them with keyboard if you know the correct number of tabs to press. But you can't *see* them.
The whole point of the Requires: system-logos is so that we get the required logos. I doubt that there's much we can do to work around gtk's failure mode and I don't think it's worth our time if we can.
*** This bug has been marked as a duplicate of bug 1252252 ***