[Arkan1k]

I'm guessing the only way this will happen is by duplicating a node. As the nodes are all connected and we need one for the top height, and one for the lower height of the cliff. By adding another node, it will change the vertical and horizontal counts of nodes in a .nw file.
So the rendering in the Graal engine may be screwed around a bit.

Another take on Polo's reply I just noticed.