Ok, I have looked at the code and it is a cutter comp error. If you use a 2mm tool it works OK, anything larger cause an increasing gouge. it looks like the lead-out arc specified in the shapes file is to short. The R format arc may be part of the problem.
I'm not sure how I'm going to fix this one, I'm still working on it. But for now you seem to have a fix.
damn, I hate cutter comp !!!
ron ginger