How is that a bug when they say that's what the spec says. Also, both Edge and WebKit are going to adopt that behaviour since it makes sense.

I think there's one more reason people see less of Firefox. I know a LOT of people who have set their user agent string to Chrome to stop the idiotic banners on websites telling me to use Chrome even through the website works perfectly on FF. I hate it even more when websites simply won't allow me to load the page when I'm on FF.