webutil_host.host where filepath has spaces breaks with java 8u291

Some functions in our application allow the export of data in csv format; this is written to a file on the server then the user is prompted for a local path and filename and the file copied there. Then if required we open it in excel like so:

  If :FILE_BLK.CHECK_OPEN_EXCEL = 1 Then -- Open Excel

   Webutil_host.host('cmd /c start excel /e "'||:FILE_BLK.TEXT_FILE_NAME||'"');

  End If;

This has stopped working on upgrade to 8u291 - it seems to have lost the double quotes. According to the release notes "Less Ambiguous Processing of ProcessBuilder Quotes on Windows