I’m not sure I understand your description.
Are you describing
A) that the torch cuts 1mm or so into the start point kerf after completing a 360 deg cut around the shape contour ?
or are you describing
B) that the torch cuts from the end of the last shape contour all the way back to a programmed finish point such as X0Y0 ?
and then, are you also describing that you had previously run sheetcam and the post processor on a different computer yielding good results on the CNC plasma table ?
It may be that you should just send a support.zip file to sales@sheetcam.com along with a photo or two of the problem.
Creating a Sheetcam Customer Support file