We are experiencing a similar issue on a client site and tracked it down to pages on which the template included <jdoc:include type="message" />, which renders a <div> with id "system-message-container" for Joomla messages.
To ensure it wasn't a conflict with other components, I did a clean Joomla install and the issue was the same.
There are no jquery/javascript errors.
Removing <jdoc:include type="message" /> from the template index.php will resolve the issue but is not a realistic solution.
I've done a video demonstrating the issue at
axses.com/vids/joomla-error.mp4
Please provide further guidance as to how to permanently resolve this problem.
We are using the latest versions of Joomla and CMC - Mailchimp.
Thank you.