QCAD seems either to mishandle or ignore svg group transformations altogether.

Importing the attached file into QCAD renders the largest polygon (polygon18) to be rotated and misplaced. This is shown in actual.png. The expected result (original Inkscape renedering) is shown in expected.png.

Looking at the code of the original drawing it can be observed there is a transformation applied to the group which polygon18 is in:

 <g
   style="stroke-width:0.35433099;stroke-miterlimit:4;stroke-dasharray:none"
   id="g20"
   transform="rotate(-90,316.66796,298.95141)" >
   <path
      inkscape:connector-curvature="0"
      id="polygon18"
      d="..." />

Removing the 'transform' attribute produces virtually identical (erroneous) rendering in Inkscape as well.