If I read it right, you have converted the edges of a polygon, with a hole, to crate a spline, for RC, however you would need to remove the diagonal spline which is causing the error. Basically it will be a single spline but have two disconnected parts, the outer one and the inner one, having a spline connecting the outer and inner, means RC sees only the one spline and fills the areas. Hope that cures your problem.