No. It's the websites.

If I used Chrome, I could see this happening. But it happens on both Edge & Firefox.

I thought you were referring to this: https://underpassapp.com/news/2025/7/5.html

It looks like the pop up is part of the browser UI in Chrome, and displayed as part of the website if using non-Chromium browsers. I block ads and don't use Chrome, so I don't see any version of this often.

This happens exactly because you're not on Chrome. For some reason the sign in with Google pop up only triggers on non-chrome browsers. Especially on Firefox.

Is it not happening on Chrome even when you don't have the browser itself logged into a Google account?