Here too, still having this bug in 1.8.9. I was building a sky spawner on my Realms server at Y=180 above the ocean and no mobs spawn, even though some annoyed me while building it. When I relog into the world sometimes 4 or 5 mobs spawn inside the spawner, but no more. When I built the spawner in a flat creative single player world, it worked like a charm.
Erik Schaumlöffel
Here too, still having this bug in 1.8.9. I was building a sky spawner on my Realms server at Y=180 above the ocean and no mobs spawn, even though some annoyed me while building it. When I relog into the world sometimes 4 or 5 mobs spawn inside the spawner, but no more. When I built the spawner in a flat creative single player world, it worked like a charm.