The green and red row thumbs up/down icons in the message list, used to indicate to the user if the message is spam or not, can sometimes act up and show a message as spam, even though the row is highlighted red and the status column indicates that the message is "good". This only happens now and again, maybe as often as once a week - probably less, but sometimes it can happen twice in a week.
I've attached a screenshot showing this, as well as the message evaluation to prove that MailWasher Pro has indeed evaluated the message as good.