Here are some steps that may provide helpful for you as they have worked in the past.
Most "crop circles" are caused by non-tangent arc segments, because BobCAD uses the corner rounding method rather than the straight corner method. That is it creates an arc around a corner to make a corner. The following will work in most cases involving splines.
1. Select All of your geometry.
2. Click on Change => Reorganize => Clean-up and Optimize (to get everything in sync)
3. Click on Change => Reorganize => Make Arcs Tangential
4. Input .001 for the Minimum acceptable angle and 15 for the Max Angle for correction.
5. Click OK.
6. Now generate your Toolpaths.
Routine #2 is to eliminate the use of arcs completely by interpolating the Toolpath, which removes all arcs from the program and replaces them with faceted line moves (which can be small enough to provide clean arcs on the finished part). I will not post this one today, but if you would like to know how, just say the word.