I'm having some odd issues when rendering with mental ray as of late. Any time i add a light other than the default light to the scene strange artifacts start showing up in the shadows of my models.

I'm attaching an example of what I'm talking about.

There is no geometry on the model that could be producing those sharp points, and I'm completely baffled as to why they are showing up.

To clarify, rendering with anything other than mental ray is not an option for me. I also believe that there must be a simple solution to my problem, so I'm hoping some of you maya veterans can help me out here. I am currently using version 8.5 of the software, and I am rendering using Production: Fine Trace settings in mental ray. I've also included the physical sky and sun, but the artifacts occur as soon as any other type of light is added to the scene.

My first guess is that it's a normals issue, but I can't seem to get it resolved. Any attempts at fixing it so far have resulted in worse artifacts.

Thanks in advance for any assistance you all can lend.