Since the update to Android12 the message saying that an SMS is a no-reply message flickers annoyingly at the bottom. I guess it has to do with the screen rounded edges and the use of swipe mode (no “buttons”) . I leave a video showing the problem, although the flickering rate is not captured so well. screen capture
Did you check what’s behind the “learn more” button?
When I search for the exact message, there are lots of people reporting this on various smartphone models. After a quick glance it seems to me that this is a bug in the Google message app which has not been fixed yet.