Problem with the formatting

Hi,

I have a problem with the plugin on one site (while it works fine on all my other sites).

When I activate the plugin, the home page looks like this: https://ibb.co/XFczmrq

(You will find the url of the site on the screenshot, I prefer not to put it here in my message).

And I have the impression that the problem persists as long as the plugin is activated on the site, even if I unchecked “active” in the plugin.
But now I’m not sure, I don’t dare to test it too long since it’s not my site.

Would you know where it comes from ?

Thank’s,
Gwenn.