I don't think time is going to fix it :-). It was showing this for over a week, before 18.1 was released and still has not updated. I just did a factory reset and update on the AppleTV and it's still showing the "update required" message under the Home app.
I have 5 Apple TVs in my house, but only use two of them as Home hubs. The second hub is running same TVOS version and is not showing the "update required" message. That one is on wi-fi where as the one with the issue is hard-wired. I may move it to wi-fi to see if that makes any difference.