newsupernova/vendor/magento/module-sales/etc/frontend/sections.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Customer:etc/sections.xsd">
    <action name="sales/guest/reorder">
        <section name="cart"/>
    </action>
    <action name="sales/order/reorder">
        <section name="cart"/>
    </action>
</config>