See picture. I just want it to scale with factor 4, but I still got the original smal part. Normally when I use the scale function it just scales, but now it seems like it copy's and scale...
My guess is that the "second model" is a surface body that could not be seen earlier because it fit around the model. Now that the model is 4x larger, the original surface can be seen in the background.
Hide or delete the surface bodies.