Maya Lighting/Baking Issue???

I'm coming up against a really weird issue in Maya. In the past I've either imported in objects from ZBrush to bake light and shadow or started in Maya with a NURBS sphere and have had no issues. Yesterday, I decided to make a hat. I created a curve and used revolve and edited from there to get the shape I wanted. Set up my lighting. So far, so good. Then I went to bake it... assigned a new material (Lambert), created a new bake set, set the Batch Bake (mental ray) options and hit convert... this is where it gets wonky. My lights are over the object shining down. When I do a render preview it looks great... highlights on the top of the hat, shadows on the bottom, but when I bake it, it's reversed. The shadows are on the top of the hat and the highlights are on the bottom. I've tried everything I can think of, and I can't figure out why. Created a NURBS sphere in the same scene to test it, and the lighting on it bakes correctly. I finally got a correct bake by turning the darned hat upside down to bake, but there has to be a better fix than that! Please help before I tear all my hair out!

Reversed normals, perhaps? Try reversing the surface direction one one axis.

Yes!! Thank you, thank you, thank you!!!