product layouts break after Hikashop v. 6.1

-- url of the page with the problem -- : antiqueswan.com
-- HikaShop version -- : 6.5
-- Joomla version -- : 5.4.6
-- PHP version -- : 8.3

Hello,

A long time ago, when I upgraded Hikashop from v. 6.1 to 6.2, the layout broke for the product list and the product details. At the time, I reverted by restoring to a backup. It's finally time for me to fix this.

I've installed the site on a staging domain so I can troubleshoot and demonstrate.

The correct layout, which is running v. 6.1, can be seen here:
List of products: antiqueswan.com/product
Product detail example: antiqueswan.com/product/regency-era-larg...ngland-dia-26-1-2-in

The broken layout, which is running v. 6.5, can be seen here:
List of products: mavendesignstudio-demo.com/swan/product
Product detail example: mavendesignstudio-demo.com/swan/product/...ngland-dia-26-1-2-in

Could you advise about where to start to correct the layout please?