When using the PdfStreamWriter to write a PdfPageSource whose content is an array of content streams, the resultant content stream contains concatenated graphic state operators. This results in error when loading the document in Acrobat Reader and corrupted page content.

When there is an abstractNum defined with the same abstractNumId in word\glossary\numbering.xml and in the word\numbering.xml, a "System.ArgumentException: An item with the same key has already been added." exception is thrown.

In other cases, the import overwrites the styles from the main document part with the ones defined in the glossary or fails to import different parts of the content. 

Currently EULA requires Telerik assemblies to be protected against unauthorized redistribution, by following specific guidelines for the different types of technology:
- for WPF: https://docs.telerik.com/devtools/wpf/installation-and-deployment/deploying-telerik-ui/protecting-telerik-assembly
- for ASP.NET AJAX: https://docs.telerik.com/devtools/aspnet-ajax/deployment/protecting-the-telerik-asp.net-ajax-assembly
- for WinForms: https://docs.telerik.com/devtools/winforms/installation-deployment-and-distribution/redistributing-telerik-ui-for-winforms

When the guidelines for WinForms or AJAX are followed (namely the call to ValidatePassPhrase() is uncommented in AssemblyProtection.IsValid() method, the following license message is added to the generated documents:
"This document was generated by a copy of Telerik Document Processing licensed for use only by '<MyApp>'."

Workaround: Set the application name as resource in the Application.Current, using the following code:

new System.Windows.Application();
System.Windows.Application.Current.Resources.Add("Telerik.Windows.Controls.Key", "MyApp");
where 'MyApp' should be replaced with the actual application name. References to PresentationFramework and WindowsBase .NET Framework assemblies should be added in order for this approach to work.

Currently, Telerik Document Processing is available only for .NET Framework and (partially) for Silverlight. Create version targeting .NET Core.

Update: There is a version of Telerik Document Processing compatible with .NET Core 3.0 in the UI for WPF suite. You can use this version in .NET Core projects running on Windows. The assemblies can be downloaded from telerik.com, the Downloads section of UI for WPF -> Betas tab. Please, note that you should have a valid license for UI for WPF in order to be able to see this version. In case you don't, you can use the Trial license by downloading a trial version of the suite. More information about this version of UI for WPF and how it can be used is available in the related blog post.

When xlsx/docx document is imported, and its main story is with non-default name ('workbook. xml'/'document.xml'), e.g. workbook2.xml/document2.xml, NullReferenceException is thrown and the document is not imported.

Note: Such documents are usually produced after conversion from a template dotx/xlsm.