Thanks Alex - yes I thought about that but I get the same behaviour with or without that hint set.
Easiest way to observe the behaviour is in your main loop just output the values of SDL_IsTextInputActive() and SDL_IsScreenKeyboardShown(window).
What I see is that both these go to 1 when I'm editing, as expected.
If I exit via "Done" on the keyboard, they reset to 0.
If I exit via the menu button, both stay at 1.
Something isn't getting cleared down.
As I say, same behaviour with or without the hint set - which is interesting in itself, because with UI event disabled then it shouldn't be closing the keyboard with the Menu button in any case should it?