V-Ray issue with toon material

Rendering V-Ray
1

Hallo V-Ray community,

I have a question about a issue when I use a toon material.
Specifically, for example when I use a rectangular light, the toon material, recreates the edges and the diagonal of the light (see the image).

Toon
Toon1383×690 481 KB

Is there a method not to make it happen?

Thanks in advance