Weird Shadows

Why is there no shadows there? Thanks for the help.

Notice the light shining on the peak in the upper left. Even though the slope in the lower left, appears to be facing the same direction, it remains UNLIT. This indicates the area IS in fact in a shadow (completely).
What happens when you tilt the directional light downwards? I would expect this to eventually (at just the right angle) reveal the shadow’s edge, does it?