In this video you can see that the sun appears to be moving with the camera, and that shadows only cast at certain positions/angles. If i move to the left the shadow disappears and another shows, if i move forward the same happens too.
It is only happening with trees, I have a point light that works in a torch and it casts shadows on the wooden support beams of the house. They stay where they are and do not produce the same effect as trees.