how do i fix this?
[04-Apr-2024 12:45:42 UTC] Request URI: /ajax.php?act=ajaxOnePageCheckout&method=updatePaymentMethod, IP address: 207.68.237.174
#1 trigger_error() called at [/var/www/clients/client1/web3/web/includes/classes/order.php:334]
#2 order->cart() called at [/var/www/clients/client1/web3/web/includes/classes/order.php:38]
#3 order->__construct() called at [/var/www/clients/client1/web3/web/includes/classes/ajax/zcAjaxOnePageCheckout.php:519]
#4 zcAjaxOnePageCheckout->updatePaymentMethod() called at [/var/www/clients/client1/web3/web/ajax.php:85]
--> PHP Notice: Malformed value for session-based shipping module; customer will need to re-select: false in /var/www/clients/client1/web3/web/includes/classes/order.php on line 334.
zen version 5.6c and opc version 2.3.12 (2022-04-03)