Hi Dan,
Thanks for taking the time to review the Trial version of Cut2D.
The circles are caused by Mach3 being set to read G2 / G3 circular arc segments using Absolute Coordinates. The Vectric postp's are saving the toolpath code using Incremental Coordinates.
This is easily changed in Mach3 on the Config screen (thanks Gerry)
Let me know if you need any assistance with this.
Tony