Hi Long, Thanks for the quick reply. I created a work around, but the issue still exists. (I had to present the site yesterday, but I have switched it back to the broken version today.)
The issue happens when I use the default WP latest posts page. In WP Admin Settings > Reading, if I set "Your homepage displays" to "Your latest posts" then the view does not use the correct post. I have put this shortcode in the posts list using the new WP theme editor like this: https://cln.sh/dNr79H but it continually only renders the First (most recent) post - like this:L https://cln.sh/gFbeKj - rather than the current post in the loop.