I had someone send multiple copies of the same file and each had the comments missing.
I then turned the Word docx into a Word.zip file and looked at the entry for comments.
The comment reference IDs were shown but the comments were missing any content. So my guess is a file corruption for some reason during transmission, as the file was displayed at the originator end?
The comments.xml at fault was:
<?xml version="1.0" encoding="UTF-8" standalone="true"?>
-<w16cid:commentsIds mc:Ignorable="w14 w15 w16se w16cid wp14"
.....
.....
<w16cid:commentId w16cid:durableId="1E08806E" w16cid:paraId="128C1B84"/>
<w16cid:commentId w16cid:durableId="1E08806F" w16cid:paraId="49BB4D80"/>
</w16cid:commentsIds>
Should have looked like:
<?xml version="1.0" encoding="UTF-8" standalone="true"?>
-<w:comments mc:Ignorable="w14 w15 w16se w16cid wp14"
.....
.....
-<w:comment w:initials="n" w:date="2018-01-17T14:54:00Z" w:author="nicholaswade" w:id="0">
-<w:p w:rsidRDefault="00323099" w:rsidR="00323099" w14:textId="4A99632E" w14:paraId="55C551B6">
-<w:pPr>
<w:pStyle w:val="CommentText"/>
</w:pPr>
-<w:r>
-<w:rPr>
<w:rStyle w:val="CommentReference"/>
</w:rPr>
<w:annotationRef/>
</w:r>
-<w:r>
<w:t>A comment</w:t>
</w:r>
</w:p>
</w:comment>
-<w:comment w:initials="n" w:date="2018-01-17T14:54:00Z" w:author="nicholaswade" w:id="2">
-<w:p w:rsidRDefault="00323099" w:rsidR="00323099" w14:textId="59CC4AF9" w14:paraId="797EAE0E">
-<w:pPr>
<w:pStyle w:val="CommentText"/>
</w:pPr>
-<w:r>
-<w:rPr>
<w:rStyle w:val="CommentReference"/>
</w:rPr>
<w:annotationRef/>
</w:r>
-<w:r>
<w:t>A comment</w:t>
</w:r>
</w:p>
</w:comment>