Willem, I just set up a new file with a box and the ground plane. I set the rdk Sun to Here, Seattle and 12 noon, no DST, and rendered, I then set up an animation with the same lat/long, date and time and let it render. I opened both on seprate layers in a Photoshop document and as far as I can see they are identical as far as the shadow goes. I think on the one that seemed to fail last night I accidentally left DST on in the rdk Sun.