This seems to be an issue with Word. In the modern CSS specification (and I assume SVG), "transparent" is equivalent to "rgba(0,0,0,0)", and you may wish to use that instead if you need to support older programs.
Hi,
we found a solution by replacing all fill=‘transparent’ by fill=‘none’ in SVG-grafics
This works for MS-Word versions which don’t support ‘transparent’.
Kind regards,
Josef