openxml : track changes not found in word document

Question

I parse MS Word documents with OpenXML to find track changes with a Author value in order to blank them. It works except for one particular Word document and I don't know why. Only 6 track changes out of 9 are found.

This is how I look for track changes :

 var file = Path.GetFileName(filePath);

  using (WordprocessingDocument document = WordprocessingDocument.Open(filePath, true))
  {
    var types = typeof(OpenXmlCompositeElement).Assembly.GetTypes()
                .Where(p => !p.IsInterface && p.GetProperty("Author") != null && p.GetProperty("Author").PropertyType.Equals(typeof(StringValue)))
                .ToList();

       var body = document.MainDocumentPart.Document.Body;
       var changes = body.Descendants().Where(x =>types.Contains(x.GetType()));
  }

Is there a better way to achieve this ?

I have also tried by passing the list of types found on this page but the result was the same. Still these 3 ignored track changes.

EDIT

Using Open XML SDK Productivity tool, here's one of the node that should be found as a track change but is missing by the code above :

  <w:ins w:id="283" w:author="Mr Smith" w:date="2019-09-11T12:34:00Z">
   <w:r w:rsidR="008458AA">
    <w:rPr>
     <w:rFonts w:ascii="Arial" w:hAnsi="Arial" w:cs="Arial"/>
    </w:rPr>
    <w:t>
     2
    </w:t>
   </w:r>
  </w:ins>

Answer 1

I found the problem.

The line var body = document.MainDocumentPart.Document.Body; does not include footer and header !

So I also have to search for track changes within footer and header.

eg for footer :

 var footer = document.MainDocumentPart.FooterParts.ToList();
 var footerChanges = new List<OpenXmlElement>();
                footer.ForEach(f => 
 footerChanges.AddRange(f.Footer.Descendants().Where(x => 
 types.Contains(x.GetType()))));