Surface Divide Error

Hello All,

I am not sure why my surface is not dividing properly, once I use the divide domain component it generates a new surface that goes out of the original surface boundary. I generated this surface in rhino from a curve and then applied the patch command to fill the surface. I dont know how I would generate the surface in Grasshopper. But none the less it still does not work properly. Please help me, I have no idea why its not dividing  the surface I generated.