Javascript exception during load on of page

Dear Mr. Miyoshi,

Thanks for the great contact plugin.

I noticed a problem during page loads with FireFox inspector window open.
It gives me an exception error “ReferenceError” on the main window, after:

/* <![CDATA[ */
var _wpcf7 = {"loaderUrl":"https:\/\/engineering-spirit.nl\/wp-content\/plugins\/contact-form-7\/images\/ajax-loader.gif","recaptcha":{"messages":{"empty":"Graag verifi\u00ebren dat je geen robot bent."}},"sending":"Verzenden ...","cached":"1"};
/* ]]> */
</script>

It seems to me that this is part of the recaptch code.
You may check it on https://engineering-spirit.nl/.