Error 'System.InvalidOperationException: Stack empty' when importing a word document in a memory stream into a RadFlowDocument
Using the Telerik assembles in ABL

The last line of the following code fails when a specific word document is used as the wordDocument source:

USING System.Text.RegularExpressions.*.
USING Telerik.Windows.Documents.Flow.FormatProviders.Docx.*.
USING Telerik.Windows.Documents.Flow.*.
USING Telerik.Windows.Documents.Flow.Model.Editing.*.
USING Telerik.Windows.Documents.Flow.Model.*.

DEFINE TEMP-TABLE ttImage NO-UNDO
    FIELD cImageName AS CHARACTER FORMAT "X(125)"
    FIELD bFile      AS BLOB
    INDEX imageName AS PRIMARY UNIQUE cImageName.
    
DEFINE VARIABLE cFile        AS CHARACTER                                                              NO-UNDO.
DEFINE VARIABLE mDocument    AS MEMPTR                                                                 NO-UNDO.
DEFINE VARIABLE iSize        AS INTEGER                                                                NO-UNDO.
DEFINE VARIABLE oMemStream   AS System.IO.MemoryStream                                                 NO-UNDO.
DEFINE VARIABLE iByteCount   AS INTEGER                                                                NO-UNDO.
DEFINE VARIABLE docxProvider AS Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider NO-UNDO.
DEFINE VARIABLE document     AS Telerik.Windows.Documents.Flow.Model.RadFlowDocument                   NO-UNDO.

cFile = "11.docx".

// Copy the document into a BLOB  
CREATE ttImage.
cImageName = cFile.
COPY-LOB FILE cFile TO bFile.
  
// Copy the BLOB into a MEMPTR
COPY-LOB ttImage.bFile TO mDocument NO-CONVERT.

// Write the MEMPTR byte by byte, to a MemStream object 
iSize = GET-SIZE(mDocument).          
oMemStream = NEW System.IO.MemoryStream(iSize).
DO iByteCount = 1 TO iSize:
    oMemStream:WriteByte(GET-BYTE(mDocument,iByteCount)).
END.   
SET-SIZE(mDocument) = 0.

// Import RadFlowDocument from docx format object
docxProvider = NEW Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider().
document = docxProvider:IMPORT(oMemStream).

When the code runs the following is listed in the PAS agent log:
2023-07-05T12:18:45.601+0100 011060 006304 1 AS-10 ROOT:r:0000bf90 -- (Procedure: 'BusinessComponents/generateDocPdf' Line:1643) ----->Document = docxProvider:IMPORT(oMemStream)
2023-07-05T12:18:47.830+0100 011060 006304 1 AS-10 ROOT:r:0000bf90 -- (Procedure: 'BusinessComponents/generateDocPdf' Line:2658) System.InvalidOperationException: Stack empty.
 

This is a known Telerik assembly bug - https://feedback.telerik.com/document-processing/1569098-wordsprocessing-document-containing-group-element-with-no-content-control-inside-this-part-causes-invalidoperationexception

Upgrade the Telerik libraries to version R3 2022 or later.