Hi Tom,
It looks like the issue is caused by this code in your functions.php.
//Defer Pasing JavaScript for entire website, including Plugins, but without jQuery.js
//Feel free to change "async" to "defer". $files will be excluded
function defer_parsing_of_js($url)
{
//Specify which files to EXCLUDE from defer method. Always add jquery.js
$files = array('jquery.js');
//let's not break back-end
if (!is_admin()) {
if (false === strpos($url, '.js')) {
return $url;
}
foreach ($files as $file) {
if (strpos($url, $file)) {
return $url;
}
}
} else {
return $url;
}
return "$url' defer='defer";
}
add_filter('clean_url', 'defer_parsing_of_js', 11, 1);
Can you try commenting it out and see if the issue is still there?
Let us know how it goes. Thanks!