ERRO Warning: array_keys()

Depois da última atualiza??o, dia 19/08, esse erro come?ou a aparacer na tela do carrinho antes de finalizar a compra:

Warning: array_keys() expects parameter 1 to be array, null given in /home/customer/www/noventtareplicas.com/public_html/wp-content/plugins/woocommerce/includes/wc-cart-functions.php on line 475

Warning: current() expects parameter 1 to be array, null given in /home/customer/www/noventtareplicas.com/public_html/wp-content/plugins/woocommerce/includes/wc-cart-functions.php on line 447

Warning: count(): Parameter must be an array or an object that implements countable in /home/customer/www/noventtareplicas.com/public_html/wp-content/plugins/woocommerce/includes/wc-cart-functions.php on line 426

Gostaria de saber como resolver