Hi Steve,
It has been found that all the Portfolio is having the CS shortcode but as mentioned in my previous post. The most common reason behind this issue might be the existing Block content has been edited in the Content builder.
Regretfully, the content added through the Cornerstone editor is not editable in the Block or Gutenberg editor, and vice-versa. That’s why the edited content is not showing in the Cornerstone.
If you don’t have any backup, unfortunately, you need to create it from scratch. If it is not possible to create it from scratch and you have the backup, I would suggest you restore your backup into the stagging site, and export the portfolio from it, and import it to your live site, which may help you to recover it.
Thanks