Mail showing up marked for "followup"

I have the same issue, except that it has so far affected only my emails to one correspondent using my university email account, which is provided by Microsoft. My Mail client for all my accounts is Apple Mail. I am using a 2021 24" iMac with OS13.0 Ventura. If I click reply, the email in the inbox then says 'following up'. However I have already replied, so it is pointless to tell me when I first wrote and that I should be following it up. I can find nothing in Mail settings which would explain this, so deduce it is a Mail bug.

Thanks very much. I found and turned off 'Enable message follow up suggestions', and the two emails concerned vanished from my inbox but are still in my Sent box. The only thing that now bothers me is that the description for this setting says 'Mail will remind you about messages that haven't received responses', but the first had received a response and Mail hadn't noticed. There is still a bug, which I cannot report as I am not a developer so cannot use Feedback Assistant.