jQuery is not defined?

It is wired that my website always received the error about whether jQuery is not defined or Can’t find variable: $.

However I do not get this error when I browse my website even in different OS, Browser and also using chrome developer tools throttle to simulate slow connection.

My website script ordering is below:

<script async="" src="//www.google-analytics.com/analytics.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<script src="https://cdn.ravenjs.com/3.15.0/raven.min.js"></script>
<script>
Raven.config('https://7c5550f7f5cd49b6922877ff529a1974@sentry.io/138266').install();
</script>
<script src="/assets/js/core.js"></script>