There's this new building in Hau'oli City. Its white and it has red, blue, yellow banners with Pokeball shape at the front side and little barriers blocking the door

Thing is on the new map there are two smaller buildings: green and blue ones so just like they looked in SM. In those games there was no banners or barriers

Maybe its a new battle facility and its only avaible post game so the barriers prevents entry for now. Its weird they'd use barriers for no reason since alola has many buildings with no access so having them here suggest they may be removed.

Having a bigger battle facility in Hau'oli would make sense since this is the biggest city of the region