Braincnc,
You may want to take a look in documentation "Mach 3 CV notes".
Also just try something with equivilant cuts using Exact Stop and compare the cutting. It will be jerky going around the corners because of all the straight lines you have instead a smooth arc. Particle board ( particularly cabinet grade) has some darn hard stuff in it, such that it seemed it's possible to push back should there be any play or backlash. Additionaly, if the router assembly isn't solid you can get some spring back when say if the axis is slowing down and the cutter has more time in an area. Also saw what looked like a soft spot in the one corner and that could even contribute more to it. Have you played around with lesser depth of cuts? ie; get the accuracy you want first and then best speed will come.
Rather than making dust, use a pencil in the non working router / no z moves to trace around see how the profiles are under no cutting pressure. First step would be elimination of any Mach settings as already posted and then some playing around on your part to see what works.
Just some suggestions,
RICH