Error creating PDF document from a PDF Portfolio

I am getting an error trying to create a Aspose.Pdf.Document from a PDF Portfolio. I am not having any issues with just a regular PDF just a Portfolio.

The error is happening here:
Aspose.Pdf.Document pdf = new Aspose.Pdf.Document(fileInfo.FullName);

and the error is:
Startxref not found

Everything I am reading says thats the correct way to open the document so i am not sure what else to try at this point. Any suggestions would be great.

Thanks

@sulstad

Thank you for contacting support.

Would you please share source PDF document so that we may try to reproduce it and assist you accordingly. Before sharing requested data, please ensure using Aspose.PDF for .NET 19.2 in your environment.

I can not provide a copy of the PDF due to security reasons. I also can not go past the 17.4 DLL as our current license wont allow it. I tried using the trial version of the 19.2 but it still gave me a license error.

@sulstad

You may request for a free 30 days temporary license and if you still face the problem with latest version then please share respective PDF file with us so that we may investigate further to help you out.