Achievements stopped unlocking/progressing

When I originally started playing achievements were unlocking. Now I can't unlock any achievements nor can I progress any that are partially unlocked such as the one for discovering biomes which is 41% complete

UPDATE by [Mojang] MissMarzenia (Aleksandra Zajac)
Users reported that logging out and back in, to your Xbox account allows them to get achievements again.

[Mojang] MissMarzenia (Aleksandra Zajac)
Looks like an on and off issue - at the moment what we can observe is that on IOS devices achievements do not unlock properly, and on Android devices they sometimes work.
We are currently fixing this issue and hopefully it will be working in the next major update.
However, sadly, I can not provide any solid dates.