Storyline 360 - iframe not working when hidden at first on Firefox

Hello,

I have noticed that when embedding my story in an iframe that is is hidden at the beginning, it works on Chrome but not on Firefox.

Code sample :

<p style="display: none"><iframe title="Programme interactif Parcours équipe projet" src="https://data.valsoftware.net/07-PACKAGING/programmes_formation/Interactif/AMMON_Essentiel_Groupe_Projet/story.html" frameborder="0" width="750" height="422"></iframe></p>

<script>
setTimeout(function() {
 document.querySelector('p').style.display = 'block';
}, 2000);

// Content is displayed after 2 seconds on Chrome but not on Firefox
</script>

To reproduce, you can save the code in an HTML file and open it with both Chrome and Firefox.

Console error :

Warning: setState(...): Can only update a mounted or mounting component. This usually means you called setState() on an unmounted component. This is a no-op. Please check the code for the AccText component.

This is a minimalist code sample working on localhost, but same error happens on a server.

Thank you in advance.

Regards,