The WooCommerce built-in integration in Schema Premium core plugin is not complete 100%, hence it isn’t going to validate the whole Product markup.

Schema Premium itself is NOT 100% compatible with WooCommerce. Some schema.org properties fields will be missing – can’t be mapped– because of the way it stores products data.

Schema WooCommerce extension

We’ve released the Schema WooCommerce extension to fully integrates with WooCommerce plugin, and insure your product pages have a valid markup.

This solution makes it easier for Schema Premium users to work with WooCommerce, have a valid markup, and remove unwanted markup duplicates.

Check out Schema WooCommerce extension.