i see the same problem with our workflow. we typically export a dwg file and copy the linework into a cad drawing(carlson). and also export a custom csv points file. we are in metric and usually see about 1mm at the vertexes. i am pretty sure it is a rounding problem. check when exporting the dwg and csv how many decimal places are being exported. easy to see on the csv after the export, but less obvious on the dwg(or dxf if that is what you are using). i would guess this is your problem. hope this helps.