PDF Conversion to PDF/A-1a - Transparent Markup not working

ExamplePDF.pdf (1.2 MB)
ExamplePDF_converted.pdf (1.3 MB)

We have problems with the result of the conversion from PDF to PDF/A. In the PDF there are a couple of annotations or markups, they are transparent and you can see the Picture or text behind them.

In the converted file the highlighting of text has been removed and the other is no longer transparent.

Our code:

    private static void SavePdfDocumentAsPDFa(Aspose.Pdf.Document pdfDocument, string outputFilepath)
    {
        var tempValidationResultFilename = Path.Combine(ConversionSettings.ConversionFolder, Path.GetFileNameWithoutExtension(outputFilepath) + "_validation.xml");

        try
        {
            // Convert document to PDFa
            pdfDocument.Convert(tempValidationResultFilename, PdfFormat.PDF_A_1A, ConvertErrorAction.Delete, ConvertTransparencyAction.Mask);

            pdfDocument.Info.ModDate = DateTime.Now;

            // Save updated document
            pdfDocument.Save(outputFilepath);
        }
        finally
        {
            if (!TryToDelete(tempValidationResultFilename))
            {
                LogHelper.Warning("Could not remove validationfile [" + tempValidationResultFilename + "]");
            }
        }
    }

Notice: If you click on and move the annotation on top of the Picture(in the converted file) it will become transparent again.
Notice2: If we instead convert to PDF/A-3A both highlighted text and “annotation” will look perfect.

Is this a bug or are we missing something?

Thank full for any help we can get!

@Spekkio10

Thanks for contacting support.

We have tested the scenario in our environment and were able to notice the issue with transparency and highlighting annotation in output PDF. Therefore, we have logged an issue as PDFNET-45890 in our issue tracking system for further investigation. We will look into details of the issue and keep you posted with the status of its correction. Please be patient and spare us little time.

We are sorry for the inconvenience.