If any page dimension or orientation settings are set at the document level, any changes made to those settings for an individual page are ignored. This is true regardless of whether I use Page.SetPageSize() or Page.PageInfo.Height/.Width.
We are sorry for the inconvenience caused. While testing the scenario with the latest version of Aspose.Pdf for .NET 9.5.0, we have managed to reproduce the reported issue and logged it in our bug tracking system as PDFNEWNET-37323 for further investigation and resolution. We will notify you via this thread as soon as it is resolved.
Please feel free to contact us for any further assistance.