Board Thread:Bug Reports/@comment-28153737-20161126165102/@comment-25330335-20161127014133

Let me explain. When you deleted the majority of your region files, and copied those you saved elsewhere, all those regions were B29 regions. When you created a new world and pasted them back in, you were pasting B29 chunks into a B30 world. B30 doesn't know that those chunks are B29, so it doesn't update them, it just plays them like a B30 world. This is why the Id's are off one. You need to update the chunks before you can put them in a new world.