Vanilla chunks generating in unexplored areas

[ThatOneGuy]

So I have been using ewg on my main world for a good while now and all of a sudden when exploring out in the wilderness it has started generating vanilla world in the areas that have not been previously explored. Any idea why this would be happening? It still says that epicworldgenerator is the generator in the Multiverse worlds file. Also, how can I fix these chunks now that they have generated vanilla?