I honestly only found one site that had such a popup, and it worked on Brave with shields enabled, Chromium and Firefox.
Cannot reproduce any other such contact us bubble on any browser if I’m not signed in (like asked, do we need to be?). I did on two sites see a “Feedback” tab on the right side which showed on Chromium and Firefox, but not on Brave, but when shields were disabled, that did appear. I assume that’s not what you are referring to though?
@d0g0 do you mind showing a screenshot of what it is you’re not seeing just to confirm we’re on the same page?