Faceted shadows on landscape

I imported a landscape using World Machine, it has a resolution of 2017x2017. I created a map with a SunSky system, all movable, so no need to bake lights. I have raytracing enabled too.
The problem are the shadows Im getting on the landscape, they look faceted/jagged, half polygons. Tried changing the light but its not use, any ideas on how to fix this?