I was unable to reproduce your issue, you can download the resulting PDF files from:
https://www.gemboxsoftware.com/temp/forum-1610/gembox-document-output.pdf
https://www.gemboxsoftware.com/temp/forum-1610/gembox-pdf-output.pdf
Try again using the latest versions of GemBox.Document and GemBox.Pdf:
https://www.nuget.org/packages/GemBox.Document/
https://www.nuget.org/packages/GemBox.Pdf/
Does this solve your issue?
If the problem remains, please send us a small Visual Studio project that reproduces your issue so we can investigate it.
Regards,
Mario