I'm currently able to translate a pt-br page into pt-br, which doesn't make sense. https://br.wikimedia.org/?diff=37088
Arguably this is blocked by T37489, rather than a blocker: they need to be fixed at the same time or the "it's not a bug, it's a feature!" brwikimedia does (translating from en to pt-br even though the source is technically pt-br) would be prevented, and pains made worse.