Hi Diego,
What do you mean by the landscape crash, something like the last picture ? That means you sculpt after making road.
Ok so look at this video : https://www.youtube.com/watch?v=j6UlzbaVTh8 at 17:00 and look until the end. You will have your answer.
The plugin shouldn’t have that behavior, yes, but i am limited to a plugin, not an engine. I have no way to “capture” your sculpt and put it in my cache without changing the landscape module. Not a single delegate left by some programmer in sculpt editor mode, and i have searched 
By the way to resolve this issue, delete the cached landscape (CahedLandscape) under the landscape you have change. Assume that the previous digging is now part of your landscape. And let me know.