I have got a iPad ios 12.1, when I click on a photo on Facebook, when it is in landscape mod, it opens up in portrait mode. (The wrong way round). The same happens when I open my Facebook photo albums.
I have reset the iPad, and removed Facebook and installed it again, still the same. It only happens on Facebook photos.
if more multiple person having issue. it either the facebook app or ios issue, contact them
My iPad (iPad Pro 9.7) also started doing this recently. I think it arrived with the upgrade to iOS 12.1.
The same has happened with the YouNow app – it'll only display in portrait mode. It used to be able to rotate between portrait and landscape.
PS: I've checked – rotation lock isn't on.
Same on my iPad, only started yesterday (19/11/18) before update. I’ve also deleted app, re-installed and done the iOS update and still doing it. If I rotate my screen it rotates it correctly, but have to do that every time.