Can only imagine there are issues with specific destinations or perhaps the union is kicking off about it. Either way, it's pretty amateurish not to have your ducks in a row before you announce this, as the message goes out and then you end up with a u-turn. A quick search of the news outlets also does not show that the change in policy has been publicised, which isn't going to endear the poor crew to passengers turning up having heard BA no longer requires masks.