It's not just happening on the Pocket Edition, it also seems to be happening to me on the Windows 10 Edition. Mobs that are spawned in the world like animals also disappear on there when you move out of where they spawned. It doesn't apply to villagers, even ones you spawn with eggs. They don't disappear.
It's not just happening on the Pocket Edition, it also seems to be happening to me on the Windows 10 Edition. Mobs that are spawned in the world like animals also disappear on there when you move out of where they spawned. It doesn't apply to villagers, even ones you spawn with eggs. They don't disappear.