I seem to have this problem with certain drawings in Autocad but not all
Post the dxf file and also the gcode file from LC.
Hole piece is like 1/16th smaller
Post the dxf file before mirroring it and also the dxf files for both sides.
How much backlash do you have on each axis?
I really don't think it's a Autocad or LC problem.
RICH