Tint transformation function is used to transform Device N color in Alternate colorspace. 

To reproduce:
Print the attached document with the MS Xps printer or PrimoPDF. 

The exception is thrown during "Put" operator execution.

Load a file in RadPdfViewer, select some of the text, right click and select Copy. A sample pdf file is attached.

To reproduce: please run the attached sample project. If you reload the document, the horizontal scrollbar is not shown.

Workaround:
        public RadForm1()
        {
            InitializeComponent();

            this.radPdfViewer1.FitToWidth = false;
            this.radPdfViewer1.ViewerMode = Telerik.WinControls.UI.FixedDocumentViewerMode.None;
            this.radPdfViewer1.EnableThumbnails = false; 
            this.radPdfViewer1.DocumentLoaded += radPdfViewer1_DocumentLoaded;
            this.radPdfViewer1.LoadDocument(@"..\..\Go Air - Himanshe Ajeet Dubey - 17-01-2018 - Ranchi to Mumbai.pdf");
            Application.DoEvents();
        }

        private void radPdfViewer1_DocumentLoaded(object sender, EventArgs e)
        {
            Application.DoEvents();
            this.radPdfViewer1.FitToWidth = true;
        }

This is not a valid PDF scenario as having appearance state requires having multi-state appearances. However, we should handle this invalid document scenario on our side so that the app does not crash with NullReferenceException.

This exception seems to be related to AES algorithm PaddingMode property. 

This is reproducible for images with FlateDecode and predictor value in the range between 10 and 15. As an example you may take a look at the DecodeParms property in the following image PDF dictionary:

<< /BitsPerComponent 8 /ColorSpace /DeviceRGB /DecodeParms << /BitsPerComponent 8 /Colors 3 /Columns 1024 /Predictor 15 >> /Filter /FlateDecode /Height 2868 /Subtype /Image /Type /XObject /Width 1024 /Length 1236707 >>

The issue is reproducible only on Windows XP. On newer versions of windows, the images are rendered as expected.

WORKAROUND: You may try implementing custom filter that handles the CMYK scenario. How to implement custom DCTDecode filter is described in this documentation article:
https://docs.telerik.com/devtools/winforms/pdfviewer/customize-and-extensibility/customize-pdf-rendering

This is Unicode (UTF-16BE) encoding for the Adobe-GB1 character collection; contains mappings for all characters in the GB18030-2000 character set.

Described on page 443 in Pdf Reference 1.7.

structure
The hierarchical document structure is a means to describe the PDF document structure, which is currently not supported. See 10.6.1 Structure Hierarchy on 856 page of the PDF specification for details.
This document structure is an alternative to the standard PDF structure and most non-Adobe software does not support it.

The document might have been created with Adobe software like Adobe LiveCycle Designer. Very often the document contains some fallback text in the standard PDF structure like:
"Please wait... If this message is not eventually replaced by the proper contents of the document, your PDF viewer may not be able to display this type of document."
"The document you are trying to load requires Adobe Reader 8 or higher. You may not have the Adobe Reader installed or your viewing environment may not be properly configured to use Adobe Reader. For information on how to install Adobe Reader and configure your viewing environment please see  http://www.adobe.com/go/pdf_forms_configure."
"For the best experience, open this PDF portfolio in Acrobat X, Reader X, or later."

Please refer to the attached sample screenshot demonstrating how the document look in Adobe and in RadPdfViewer.

The current implementation relies on valid cross-reference table offsets in the PDF documents so that PDF objects are easily found and parsed. However, a mechanism for importing documents with invalid cross-reference table offsets may be implemented.

The attached project shows how to repair such documents.

With the R1 2021 version of our controls RadPdfViewer is using the RadPdfProcessing library model. In this scenario, the PDF document contains images with sizes 87380, 87654. Internally the control is using RenderTargetBitmap to draw the image. So when we pass these values as Width and Height to the constructor of this object an exception occurs. This is a limitation of the RenderTargetBitmap class. It can be reproduced outside of the RadPdfViewer.

RenderTargetBitmap bmp = new RenderTargetBitmap(87380, 87654,96,96,PixelFormats.Pbgra32);

As a workaround, we can use the old rendering engine of the control by setting the RadPdfViewer.UsePdfProcessingModel property to false.