There is a problem with mob spawners on minecraft, I have a survival only realm and every mob spawner i find works when i go away from the spawner and come back the mob inside the spawner dissapears and the spawner still makes light but nothing spawns this has happend to every world and realm i own. All the mob spawners rooms are pitch black and the box is producing light but nothing is spawning please fix this it has being happening since the new minecraft came out (im on the new minecraft) please fix this extremely annoying.