PDF not always visible

I just installed the EmbedPDF module. It works, but not every time. When refreshing the document is not always displayed.
Any suggestions?
https://www.jeugdhulpcollectief.nl/index.php/component/content/article/12-artikelen/28-de-covid-19-crisis-en-verslaving-bij-jongeren?Itemid=124

Joomla! 3.9.27