Does it has a bug for rs2_project_point_to_pixel function?

static void rs2_project_point_to_pixel(float pixel[2], const struct rs2_intrinsics * intrin, const float point[3])
{
    //assert(intrin->model != RS2_DISTORTION_INVERSE_BROWN_CONRADY); // Cannot project to an inverse-distorted image

    float x = point[0] / point[2], y = point[1] / point[2];

    if(intrin->model == RS2_DISTORTION_MODIFIED_BROWN_CONRADY)
    {

        float r2  = x*x + y*y;
        float f = 1 + intrin->coeffs[0]*r2 + intrin->coeffs[1]*r2*r2 + intrin->coeffs[4]*r2*r2*r2;
        x *= f;
        y *= f;

 //the x and y have changed, but the r2 still uses the original x and y. A bug here?
        float dx = x + 2*intrin->coeffs[2]*x*y + intrin->coeffs[3]*(r2 + 2*x*x);
        float dy = y + 2*intrin->coeffs[3]*x*y + intrin->coeffs[2]*(r2 + 2*y*y);
        x = dx;
        y = dy;
    }
    if (intrin->model == RS2_DISTORTION_FTHETA)
    {
        float r = sqrt(x*x + y*y);
        float rd = (1.0f / intrin->coeffs[0] * atan(2 * r* tan(intrin->coeffs[0] / 2.0f)));
        x *= rd / r;
        y *= rd / r;
    }

    pixel[0] = x * intrin->fx + intrin->ppx;
    pixel[1] = y * intrin->fy + intrin->ppy;
}