> So "loopings" can be easy created without my control due the micro pen movments :)

Yes, that's definitely something that you should watch for.

But in this case, it sure looks like those loops are the result of an offset operation that has a large offset distance in an area of tighter curvature. I think maybe the main shape was created by doing a shell of the outside surface to give it thickness? Doing a shell involves creating an offset surface, if the offset distance is large in an area where the surface has a tight bend in it, then it can cause the offset to fold over on itself like you have here.

- Michael