Sounds like either your input body or your tool body is a Convergent Body? Is that right?
The cause of this problem was a spline with grade * 1 * grade * 3 * and the message disappeared. Problem solved. I'm using Global Shaping and for some reason I do not know that happened.
Thanks for the reply, my friend!
Not sure if my comment helped at all, but I'm glad you got it figured out. :-D