The problem of converting a surface obtained by intersection of an ellipsoid and a cuboid into a B-spline surface

// Constructing the sphere
gp_Sphere SphereMir(gp_Ax3(gp_Pnt(0, 0, 0), gp::DZ()), m_RadiusX);
BRepBuilderAPI_MakeFace SphereMirMaker(SphereMir);
TopoDS_Shape SphereMirrorShape = SphereMirMaker.Shape();

// Define a transformation matrix for stretching the sphere in y and z directions
gp_GTrsf trsf;
trsf.SetValue(1, 1, 1.0);
trsf.SetValue(2, 2, m_RadiusY / m_RadiusX);
trsf.SetValue(3, 3, m_RadiusZ / m_RadiusX);
TopoDS_Shape ellipsoid = BRepBuilderAPI_GTransform(SphereMirrorShape, trsf).Shape();

// Create a cuboid
TopoDS_Shape box;
gp_Pnt pCentrol_Point(Point.X() -25, Point.Y()-50, Point.Z()-25); // This Point is a point on the surface of the ellipsoid
BRepPrimAPI_MakeBox makeBox(pCentrol_Point, 50, 100, 50);
box = makeBox.Shape();

// Obtain the faces obtained by the intersection
BRepAlgoAPI_Common section(ellipsoid, box);
section.Build();
TopoDS_Face Ellipface;
TopExp_Explorer explorer(Ellipintersection, TopAbs_FACE);
while (explorer.More()) {
Ellipface = TopoDS::Face(explorer.Current());
break;
}

// Convert to a B-spline surface
BRepBuilderAPI_NurbsConvert nc;
nc.Perform(Ellipface);
TopoDS_Shape shape = nc.Shape();
TopLoc_Location loc;
Handle(Geom_Surface) surf = BRep_Tool::Surface(TopoDS::Face(shape), loc);
Handle(Geom_BSplineSurface) bsplineSurface = Handle(Geom_BSplineSurface)::DownCast(surf);

// Convert the B-spline surface back to TopoDS_Face
TopoDS_Face B_Face = BRepBuilderAPI_MakeFace(bsplineSurface, Precision::Confusion());

In theory, Ellipface and B_Face should be the same shape, but now B_Face shows the same shape as ellipsoid, as shown in the attached figure, the local face in the figure represents Ellipface.

Moreover, the above problem does not occur if the sphere is not stretched using gp_GTrsf.

But I need to define the ellipsoid by defining the radius of the x, y, and z axis, so I'm not sure how to solve this problem now? If there are experts who know this aspect, I hope to communicate with you.

Thanks in advance!