Same problem here. One side of the circle ends with a flat. If the circle is about 8 inches, the flat is about 1 inch long. We generated code with lcam, cut2d from vectric and with Rhinocam. We used lines segments to create the circles, and we used arcs to create the circles. We used a stepper based machine and a servo based machine. Within small differences, the problem staid the same. We continue to look into paramaters here and willa lso try and run EMC on a PC to see if there is a mach problem. It seems that this issue is a tricky one...
Cheers
Rainer
PS:Nice meeting you in York Graham, Brian, and the rest of the gang!