Weird Shadow Bug with Lighting

I have a night scene in which the moon is half a sphere set way up in the sky to give a false sense of a moon. It looks like this:


As you can see out to the right there is a big black round shadow there which I assume is the moon or something else that goes in front of the light but I can’t seem to figure out what it is.
It came after I rebuild the light once and I can’t make it go away now.

Okay never mind. Apparently adjusting the light source a few degrees up it fixed itself. That’s so weird.