Yep, you started a Reply, then came back to it later and finished it. After you post and go back to the main page, it looks like that. Except I use a different theme.
Time frame for wacky not sure, hour maybe? But it happens to me. Starting to make a reply, get distracted, come back. It then shows that I have not read most posts.
Log out and back in.
I spend way too much time here.