Hi,
Thank you for considering Aspose.
I have test your code and I am unable to reporduce the error. I am sending you the pdf file which i generated from your code. Are you using the latest version of Aspose.pdf.
Thanks.
I am able to reproduce this error. I have logged this issue as PDFNET-3662. I will discuss this with the developers and we will let you know as soon as solution is found.