I can not see the site since it requires a password to view…
The Google Maps API key message in the console is not the issue as presently the key is not required and this is just a warning. Sometime in the future Google is going to require this key as far as I know, they have not even said when. You’re seeing this message because the browser key is not actually being utilized yet. That change will come in the next update. So this warning will go away.
The issue, I suspect from previous experience, is that another plugin or maybe the theme is doing something with images and did not take into account or exclude the Google image map tile images. I’ll need to see the page having to issue to determine the source of the issue and what the fix might be. The login details can be posted here as a private reply.