According to the PDF Specification: The first entry in the table (object number 0) is always free and has a generation number of 65,535;

An invalid xref table:

xref
1 3
0000000010 00000 n
0000000124 00000 n
0000011290 00000 n

xref
0 4
0000000000 65535 f
0000000010 00000 n
0000000124 00000 n
0000011290 00000 n

The table border styles are not imported correctly with a specific document.

Workaropund:

RtfFormatProvider provider = new RtfFormatProvider();
RadFlowDocument document = provider.Import(File.ReadAllText(@"..\..\test.rtf"));
 
PdfFormatProvider pdfProvider = new PdfFormatProvider();
var tables = document.EnumerateChildrenOfType<Table>();

foreach (var table in tables)
{
    table.Borders = new TableBorders(new Border(BorderStyle.None));
}


using (FileStream stream = File.OpenWrite(@"..\..\result.pdf"))
{
    pdfProvider.Export(document, stream);
}

With the current implementation, the permissions are ignored on import.

As a side note, there is an option to set permissions on export: UserAccessPermissions.

Table cell content is not displayed after PDF export if cell Preferred Width is too small.

Workaround: Make cell Size(Preferred Width) big enough for the contents to fit.

Support for validating signature fields signed with signatures that are encoded in ETSI.RFC3161 encoding should be added.

Currently, when invoking the Signature`s TryValidate() method an exception is thrown: NotSupportedException: 'No signature validation handler was found for the subfilter: ETSI.RFC3161'