Hi Jay, I figured it out! I checked the recordset in the pages.php file and it's set to group by two columns:
GROUP BY ContentGroup, ContentPageSetOrder
For some reason, the value in ContentPageSetOrder has at some point changed from NULL to 0, so it was being treated as two separate 'groups' in the query (see screenshot of query attached, "About Us"). If you change the 0 values in the affected rows to NULL, you'll end up with just the one content group and it will then only display once.
