Dear Lovefishing, as the URL structure of PrestaShop and WordPress ecommerce is different e.g. PrestaShop contains product IDs in URLs while PrestaShop Woocommerce not. So If you have migrated to WP, it seems that some of the links are not properly redirected or the link juice is not transferred. Do you have though to redirect it using a module, if not then you have to think for this option.
