Conversion from doc to docx breaks Visio object

So i have used Gembox.Document to convert a bunch of files from doc to docx. However afterwards those documents that contains an embedded Visio object is converted to an unknown object where some of the elements are missing, but not all. I can’t find that this is not supported, am i doing something wrong with just opening a doc document and saving as docx.
Attached is how it should look, and how it looks after conversion:

The following is my conversion code:

  if (document.Extension.Equals(".doc", StringComparison.InvariantCultureIgnoreCase))
  {
      var fileName = Path.GetFileNameWithoutExtension(document.OldPath);
      var doc = GemBox.Document.DocumentModel.Load(document.OldPath);
      document.Extension = ".docx";
      doc.Protection.StopProtection();
      var savePath = $@"{migrationFolder}\{section.SectionNumber}\{document.DocumentInitial}\{document.DocumentName}{document.Extension}";
      doc.Save(savePath);
      document.MovedConvertedPath = savePath;
  }

Hi Søren,
I’m afraid that without investigating that DOC file I cannot say anything for sure.
Can you send us your DOC file so that we can reproduce this issue?

Hi Mario

Is there a mail where i can send the document?

Please check our Contact page.

This issue has been fixed with this NuGet hotfix release:
Install-Package GemBox.Document -Version 33.0.1498-hotfix

Or with this bugfix:
https://www.gemboxsoftware.com/document/nightlybuilds/GBD33v1498.zip