A possible workaround could be to remove the image with the invalid Uri from the RadFlowDocument before export:

Exception when trying to import symbols with the ZapfDingbats font

This is not a valid scenario, but Adobe Acrobat handles it and we should too. 

Embedding a TrueType font collection using the FontsRepository.RegisterFont method leads to glyphs with empty outlines collection. The missing outlines are caused due to an empty glyf and loca tables of the TrueType font file.

KeyNotFoundException exception is thrown when the platform type is MacintoshNonSymbolic and the encoding is WinAnsiEncoding.

The chart axes are not correctly imported when there are floating and sheet charts

The content of the merged cells is measured and affects the CenterHorizontally behavior. Only the first cell from the merged range should have content. This is the default behavior in MS excel when cells are merged as well.

Fonts that are not surrounded by curly braces cannot be imported in the RTF format

PdfProcessing: Signature field validation fails if a document is imported from a byte array of CopyStream property is false.

Workaround: Set the CopyStream property of the ImportSettings to true:

PdfFormatProvider formatProvider = new PdfFormatProvider();
formatProvider.ImportSettings.CopyStream = true;

Exported checkbox fields have state "/On " instead of "/Yes ". 

Inserting a table with more than 10K rows is very slow.

Workaround: 

Use the following approach with SpreadStreamProcessing,SpreadProcessing and PdfProcessing:

 1) Generate an xlsx document with RadSpreadStreamProcessing 
 2) Import the document from 1) with RadSpreadProcessing 
 3) export 2) to PDF

The CIDToGIDMap value is exported as an indirect object. When the value is a PdfString ist should be directly exported and not referred as an indirect object. 

When importing color space defined as an external resource name, a NotSupportedColorSpaceException: 'CS0 color space is not supported.' is thrown.

OutOfMemoryException has thrown when creating a thumbnail with the ThumbnailFactory.

This behavior is observed with binaries version 2020.2.513 or later.

Importing document containing TextBox widgets with NormalContentSource defining text properties, such as FontSize and Position, are exported with incorrect appearance when the value of the field is modified.

AcroForms are not saved when splitting a document into pages. This leads to forms not being recognized when the file is imported back.

 InvalidCastException when importing a file with missing space. The file contains no space between the objects declarations and the page content and this is why the exception occurs.

CellSelection.SetValue method causes memory leak of CellReferenceRangeExpression objects in some cases when cell value is referenced by formulas. The memory leak is small, but the remaining CellReferenceRangeExpression continue to listen to some events, causing performance issues when their number become large - the time to set the value increases with each set.

By specification, the URI property of URI Actions is encoded in 7-bit ASCII string. For this reason, our current implementation relies on that the property will be of type PdfLiteralString. However, in cases such as password-encrypted documents, the property may be encoded with PdfHexString which leads to InvalidCastException: 'Unable to cast object of type Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfHexString' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfLiteralString'.', on document import.

By specification, FitH destinations are defined with page and top position. A null value for top specifies that the current value of that parameter is to be retained unchanged. However, importing such a document with PdfProcessing leads to ArgumentOutOfRangeException:  'Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index'.