Can you help my with cloning model? Why part in my model is deleting

When i clone the model the primary part of this model is deleting . But there is primary part in original model. Code is working becose i cloning two different models. Clone of first model have primary part but clone of the second model not have primary part. (YOU CAN CHECK THERE IS SOMETHING LIKE PRIMARY PART ADDING A MODEL AND SEE THE PROPERTIES OF THIS MODEL)

IF SOMEONE WILL HELP MY AND THIS WILL WORK I CAN HELP YOU WITH YOUR PROBLEM IF I WILL CAN (sorry for errors in the text. I'm from Poland)