Bukkit

What steps will reproduce the problem?
1. get a world already used
2. set Empy as worldgen
3. tp in a random place, terrain generated like vanilla...

What is the expected output? What do you see instead?
Empy must generatore a void world without NOTHING right?

What version of the product are you using?
5.2.6

What version of the craftbukkit/bukkit are you using?
Spigot 1.8.3

Do you have an error log of what happened?
None

Please provide the result of /mw debug below:
[22:30:44 INFO]: [MultiWorld] Now printing debug information
[22:30:44 INFO]: [MultiWorld] MultiWorld version: 5.2.6
[22:30:44 INFO]: [MultiWorld] Bukkit version: git-Spigot-c3c767f-33d5de3 (MC: 1.8)
[22:30:44 INFO]: [MultiWorld]
[22:30:44 INFO]: [MultiWorld] --<[Modules]>--
[22:30:44 INFO]: [MultiWorld] [State, pluginName]
[22:30:44 INFO]: [MultiWorld] [Unloaded, EndPortalHandler]
[22:30:44 INFO]: [MultiWorld] [Unloaded, EnderChestBlokker]
[22:30:44 INFO]: [MultiWorld] [Unloaded, WorldChatSeperatorPlugin]
[22:30:44 INFO]: [MultiWorld] [Unloaded, GameModeChancer]
[22:30:44 INFO]: [MultiWorld] [Unloaded, WorldSpawnHandler]
[22:30:44 INFO]: [MultiWorld] [Unloaded, NetherPortalHandler]
[22:30:44 INFO]: [MultiWorld]
[22:30:44 INFO]: [MultiWorld] --<[CommandStacks]>--
[22:30:44 INFO]: [MultiWorld] multiworld.command.DefaultCommandStack
[22:30:44 INFO]: [MultiWorld]  - /mw []
[22:30:44 INFO]: [MultiWorld] multiworld.command.DefaultCommandStack
[22:30:44 INFO]: [MultiWorld]  - /mw [debug]

by any change, is there a already existing world directy of the worldname you specified when generating the world, if yes, old chubnks will use existing on disk region files, while new chunks use the empty generator

Same problem here, create a new world and everything is just fine, but when you move to new chunks (around about 512 blocks away from 0,0) chunks will be generated just like normal survival