Strange pattern in rendering

Hi everyone. I’m very new to Blender. I only want to do shaded reliefs for maps using Blender\BlenderGis.
I tried to do something like that using this tutorial:
Everything went fine except for the fact that the final render image contained strange patterns like a mash or something like that.(see attachment).
I attached the final render and the Blender project used.
Please help me with this.
Thank you.

Bebe Onea


Calimani_Filtered.blend (504 KB)