wp_wc_disble_shipping_rates_cache.php

<?php

// essentially disable WooCommerce's shipping rates cache
add_filter('woocommerce_checkout_update_order_review', 'clear_wc_shipping_rates_cache');

function clear_wc_shipping_rates_cache(){
 	$packages = WC()->cart->get_shipping_packages();

 	foreach ($packages as $key => $value) {
 		$shipping_session = "shipping_for_package_$key";

 		unset(WC()->session->$shipping_session);
 	}
}