Looks like some of the new levels was early released to a test group of players. From time to time the game studio does A/B testing for a segment of players before new levels and features are released.
when we make games appear, it is for all and not for a certain number that must be used as a test, what tests, we do not need them. I had this 2nd series then she disappeared, why
when King puts 2 sets for Christmas, Easter and the end of July, it makes them nice for the holidays and King does not need to do any AB tests, so we have to see to stop with this system AB tests which is useless, rather than to make unhappy some players who leave the game