Load a different game prompt

Since today's maintenance break I was asked to re-enter my Apple ID. Now the game asks whether I want to load a different village, one I created to be funded by the same apple account but with a different gamecentre ID. The game was created on a different ipad over a year ago for my grandaughter to play over a weekend with us and hasn't been used since. I haven't had this message before, so what has changed? And how do I stop it happening? I have tried logging out/in of gamecentre with no luck.