When the WPSSO Shipping Delivery Time for WooCommerce add-on (aka WPSSO WCSDT) is active, it provides the WPSSO Core plugin with information about shipping zones, methods, and classes. If you prefer to exclude the Schema shippingDetails property from product offers, you can add the following filter to your WordPress child theme functions.php file:
add_filter( 'wpsso_og_add_mt_shipping_offers', '__return_false' );