2 scenes of same map, why does changes to one effect the other?

[tewdiks]

Simple enough, I made a terrain, and saved two scenes from it. Now I would like to edit one without the changes occurring to the other.

[Yokimato]

You need to duplicate the terrain (right click > duplicate will work).

Currently, you have two scenes point to the same terrain, so it would stand to reason that any and all changes to that terrain in any scene change that terrain – it doesn’t matter from which scene the terrain is edited from.