Thank you for contacting support.
We have worked with the data shared by you and have been able to reproduce the issue with below code snippet. A ticket with ID DIAGRAMNET-51673 has been logged in our issue management system for further investigation and resolution. The ticket ID has been linked with this thread so that you will receive notification as soon as the ticket is resolved.
// Call the diagram constructor to load diagram from a VSDX file
Aspose.Diagram.Diagram diagram = new Aspose.Diagram.Diagram(dataDir + "Input_File.vsdx");
// Options when saving a diagram into the PDF format
Aspose.Diagram.Saving.PdfSaveOptions options = new Aspose.Diagram.Saving.PdfSaveOptions();
// Conformance level for generated PDF document.
options.Compliance = Aspose.Diagram.Saving.PdfCompliance.PdfA1a;
// Save in any supported file format
diagram.Save(dataDir + "PDFSaveOptions_19.7.pdf", options);
We are sorry for the inconvenience.