I don't think he can or want fix this. Well, I can deal with this little problem. I have a much bigger problem, especially on the fretless neck (on the fretted neck it is only a little bit present). It has a huge and very very annoying dead spot on the G-string around the E-flat position. I try to play around it but sometimes I can't or forget and then hear the dead notes

This problem occurs more often on single-piece necks.
I mentioned this a few times to Stephen. His answer was something like: what is a dead spot?
No solution available I guess.
Now I'm looking for an affordable short-scale fretless bass but they are hard to find.