If you set a new world spawn point, the chunks around the original spawn point won't unload until a new chunk is loaded anywhere in the world.
If you set a new world spawn point, the chunks around the original spawn point won't unload until a new chunk is loaded anywhere in the world.
Is this still an issue in the current Minecraft Snapshot 15w46a or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.