ESI + Pro Theme by Themeco

@qtwrk

Sorry for reopen this one. But its not solved. Exactly same here.

Pro Theme from Themeco with Cornerstone. When ESI is enabled Cornerstone will not load anymore.

could you please check , on both ESI ON / OFF cases , the HTML source code and JS request lists ? see if they are identical or missing something ?

Not identical. It stops on half because of an console error

SyntaxError: Unexpected EOF

Errors reference will be here

<script type='text/javascript' id='wp-api-fetch-js-after'>
wp.apiFetch.use( wp.apiFetch.createRootURLMiddleware( "https://www.example.com/wp-json/" ) );
wp.apiFetch.nonceMiddleware = wp.apiFetch.createNonceMiddleware( "[an error occurred while processing this directive]
" );
wp.apiFetch.use( wp.apiFetch.nonceMiddleware );
wp.apiFetch.use( wp.apiFetch.mediaUploadMiddleware );
wp.apiFetch.nonceEndpoint = "https://www.example.com/wp-admin/admin-ajax.php?action=rest-nonce";
</script>

or

<script type='text/javascript' id='wp-api-request-js-extra'>
        /* <![CDATA[ */
        var wpApiSettings = {"root":"https:\/\/www.example.com\/wp-json\/","nonce":"[an error occurred while processing this directive]
        ","versionString":"wp\/v2\/"};
        /* ]]> */
        </script>