greeting_dialog_display hide attribute doesn’t work

greeting_dialog_display has no effect, it’s still showing up

<div id='fb-root'></div>
  <script>(function(d, s, id) {
    var js, fjs = d.getElementsByTagName(s)[0];
    if (d.getElementById(id)) return;
    js = d.createElement(s); js.id = id;
    js.src = 'https://connect.facebook.net/en_US/sdk/xfbml.customerchat.js#xfbml=1&version=v2.12&autoLogAppEvents=1';
    fjs.parentNode.insertBefore(js, fjs);
  }(document, 'script', 'facebook-jssdk'));</script>
  <div class='fb-customerchat'
    attribution='wordpress'
    greeting_dialog_display='hide'
    page_id='1515644428706165'
  >
</div>     

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