Convert pdf to grayscale not work with under line

version aspose pdf for .net
I use the below code to convert pdf to gray scale, but in the result.pdf, the under line keeps the color,only text change to gray scale.

        Document mDoc = new Document(inputPath);
        Aspose.Pdf.RgbToDeviceGrayConversionStrategy strategy = new Aspose.Pdf.RgbToDeviceGrayConversionStrategy();
        for (int idxPage = 1; idxPage <= mDoc.Pages.Count; idxPage++)
            Page page = mDoc.Pages[idxPage];


Thank you for contacting support.

Would you please share source and generated file so that we may investigate further to help you out.

color_grayscale.pdf (13.9 KB)
color.pdf (13.5 KB)
Hi Farhan,
Thanks for the reply. Here are the input(color.pdf) and output(color_grayscale.pdf)


Thank you for sharing requested data.

We have worked with the data shared by you and have been able to reproduce the issue in our environment. A ticket with ID PDFNET-46153 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.

We are sorry for the inconvenience.

The issues you have found earlier (filed as PDFNET-46153) have been fixed in Aspose.PDF for .NET 21.7.