newsupernova/vendor/temando/module-shipping-m2/etc/frontend/sections.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Customer:etc/sections.xsd">
    <action name="checkout/onepage/saveOrder">
        <section name="checkout-fields"/>
    </action>
</config>