try to save step file after scaled shape but i loose color

Hi everyone,
this is my first post.

I try to scale a step object and save to another step file
when i transform the shape it works but I lose the color.
i try to copy the color of each face from the original to a scaled one but I receive this error:
Exception caught: A null Label has no attribute.

I put in attachment the step file I try to scale and save

I try to follow this tutorial.
https://www.youtube.com/watch?v=dq2-evewPeA

Here my code to save step file.

 
bool WriteLabelToSTEP(const Handle(XCAFDoc_ShapeTool)& shapeTool, const TDF_Label& label, const std::string& filename, double scaleFactor = 10.0) {
    // Create a writer for exporting STEP files
    STEPCAFControl_Writer writer;
    writer.SetColorMode(true);  // Make sure this is set
    writer.SetNameMode(true);
    writer.SetLayerMode(true);
    Interface_Static::SetIVal("write.stepcaf.subshapes.name", 1);
   
    TDF_Label refLabel = label;
    if (shapeTool->IsReference(label))
        shapeTool->GetReferredShape(label, refLabel);

    // Access color tool
    Handle(XCAFDoc_ColorTool) colorTool = XCAFDoc_DocumentTool::ColorTool(refLabel);

    // Retrieve the original shape
    TopoDS_Shape originalShape = shapeTool->GetShape(refLabel);

    // Apply scaling to the shape
    gp_Trsf scaleTrsf;
    scaleTrsf.SetScaleFactor(scaleFactor);
    BRepBuilderAPI_Transform transformer(scaleTrsf);
    transformer.Perform(originalShape, true);
    TopoDS_Shape scaledShape = transformer.Shape();
    

    // Explore original and scaled shapes to reapply colors
    TopExp_Explorer expOrig(originalShape, TopAbs_FACE);
    TopExp_Explorer expScaled(scaledShape, TopAbs_FACE);
    
    while (expOrig.More() && expScaled.More()) {
        const TopoDS_Face& originalFace = TopoDS::Face(expOrig.Current());
        const TopoDS_Face& scaledFace = TopoDS::Face(expScaled.Current());
        

        // Debug output to check the presence of faces
        std::cout << "Original face found: " << &originalFace << std::endl;
        std::cout << "Scaled face found: " << &scaledFace << std::endl;

        Quantity_Color color;
        if (colorTool->GetColor(originalFace, XCAFDoc_ColorSurf, color)) {
            std::cout << "Color found: " << color.StringName(color.Name()) << std::endl;
            /*
            TDF_Label colorLabel = shapeTool->AddSubShape(refLabel, originalFace);
            //colorTool->SetColor(scaledFace, color, XCAFDoc_ColorSurf);
            colorTool->SetColor(colorLabel, color, XCAFDoc_ColorSurf);
            */
           

            try {
                // Your existing code inside this try block
                 // Associate color with the scaled face
                TDF_Label scaledFaceLabel = shapeTool->AddSubShape(refLabel, scaledFace);
                colorTool->SetColor(scaledFaceLabel, color, XCAFDoc_ColorSurf);
             
                
            }
            catch (const Standard_Failure& e) {
                std::cerr << "Exception caught: " << e.GetMessageString() << std::endl;
            }
            catch (const std::exception& e) {
                std::cerr << "Standard exception: " << e.what() << std::endl;
            }
            catch (...) {
                std::cerr << "Unknown exception caught" << std::endl;
            }
            
        }
        else {
            std::cout << "No color found for this face." << std::endl;
        }

        expOrig.Next();
        expScaled.Next();
    }

    // Set the scaled shape back to the label
    shapeTool->SetShape(refLabel, scaledShape);

    // Transfer the label (with the scaled shape) to the writer
    if (writer.Transfer(refLabel, STEPControl_AsIs) != IFSelect_RetDone) {
        std::cerr << "Failed to transfer label to STEP writer." << std::endl;
        return false;
    }

    // Write to a STEP file
    if (writer.Write(filename.c_str()) != IFSelect_RetDone) {
        std::cerr << "Failed to write STEP file: " << filename << std::endl;
        return false;
    }

    return true;
}

thank you for your help.
Best regards
Daniel