The stubs come from the "pure Germans", and became relatively fixed in the line.
Crosses, from what I have seen, show few or no signs of stubs. I would guess that some may show stubs in the following generations. It is at least something to watch out for. The stubs that we are talking about here is a result of a recessive gene being paired up.
Some of these NHs are crosses, and then have been crossed again. I think that it is also helpful to note that Jefferson brought more than one strain back from Germany. I understood from him that one strain was larger than the other. The larger NHs did not fair as well for some reason, but seams to have had some influence on what is out there. I did not ask him if the stubs were in one or both. At the time, I did not realize the stubs was something to watch out for.
Regardless, the gene for the stubs is out there. I believe that with thoughtful breeding, and a watchful eye, the stub subject can be put in the past. I guess with any breed or strain, there is a problem to work on.