Probably just artifacts. Run the actual preview and see what happens. At the stage of the screenshot all you're really seeing is a graphical representation of the moves the tool will make rather than the actual cut.
Dosen’t show up in preview. I have had raised lines show up in actual cutting on some other occasions so I was concerned. Could have been machanical issues though in this home grown machine. I’ll ignore them and thanks. Dan
The toolpath preview is very accurate so if they don't show up when you look at the preview then they won't be there when you machine it If there are deep lines in the machined part that don't show in the toolpath preview then the problem is almost always with the machine or the control software not the vectric software