About B-Spline curve with high number of basis function

I am doing optimization with respect to control points of B-Spline representation of a ground truth curve. I know that for B-spline representation the resultant curve will only pass through initial and final control points and rest of the points will act as polygon boundary. But, when I am working with large number of control points, after optimization I am getting a curve where it is exactly (checked with zoom) passing through the control points.

For large number of control points (control points are blue points on the red trajectory) -

For small number of control points (control points are red points) -