James Cridland - ex BBC - thinks it's internal BBC politics.

There’s an almighty fight between BBC Studios and the BBC public service. BBC Studios don’t own BBC Sounds so can’t make any announcement about it, and that’s why my BBC Studios PR person isn’t able to answer me or field any spokesperson. Meanwhile, BBC Sounds knows that its figures will look (even) worse when they’re closed internationally, so are not too keen on the whole plan, and will drag their heels on it all, and don’t want to field a spokesperson because what happens overseas really isn’t their fault. I suspect this relatively early, ... And, lest we not forget, BBC World Service Radio is not ad-funded, so they’ll be unhappy about ads - probably one reason why there’s a BBC World Service app which is also, quietly, available.

BBC Sounds international closure postponed: BBC radio overseas, and what's next

There's a BBC World Service app? I can't find it.