Terrain Auto-Generation: Fixes?

Hello all.
I was fiddling with my Pogwassek Island Railroad route, and found a bit of a geographic oddity.
I did not add this sudden rise in terrain, and it happens to go over a portion of the route. I haven’t edited the route in about two weeks, and this was not here two weeks ago. Nor was it here yesterday, when I was taking some screenshots.
Does anyone know why this happens, how to prevent it, and any quick way to deal with it that doesn't involve meticulously redoing all the terrain?
I was fiddling with my Pogwassek Island Railroad route, and found a bit of a geographic oddity.
I did not add this sudden rise in terrain, and it happens to go over a portion of the route. I haven’t edited the route in about two weeks, and this was not here two weeks ago. Nor was it here yesterday, when I was taking some screenshots.
Does anyone know why this happens, how to prevent it, and any quick way to deal with it that doesn't involve meticulously redoing all the terrain?