Thank you for the fix! You also helped me understand table syntax for Lua which helped with another filter I was using :-)

After all this effort, I discovered that the Outlook desktop client (which is the target for the HTML generated by pandoc) has deemed that the <del> tag will be treated as text to be ignored - probably because Outlook uses Word for HTML rendering and not displaying deleted text is how Word's Track Changes view works. I had to add an extra filter to use the <s> tag instead - amusingly enough, the answer for how to do that was another post by you :-), but this time on StackOverflow: https://stackoverflow.com/a/74700448