Why won't spotlight light anything above its z location?

New to Unity, so I apologize if this is something obvious.

The light is directed at a mesh and there is nothing between the light and the mesh. It does not have to do w/ that specific area on the mesh—if I move the light source, that area lights up fine. For some reason it is tied to the light source's z-location. Anything above the light's location does not light up (with the exception of the plane I'm using as the ground). See the example image where the spotlight is cut in half).

This happens w/ multiple light sources of different types.

This mesh was created following the cave generation tutorial.