Office 365 spam filters marked this message as a good piece of mail (non-spam), and then the message was marked as spam after ...

Office 365 spam filters marked this message as a good piece of mail (non-spam), and then the message was marked as spam after we processed it. This usually happens when a mail client, such as Outlook, is set up to identify messages as spam. This can also happen if your messages are routed through another filtering system after Office 365.