Problem with Get IMAP Mail Message

The robot I have gets the attachments from a email, I have the checkboxes “MarkAsRead” and “OnlyUnreadMessages” checked. But when I run the robot it gets all the messages even if there are no unread messages in my inbox. I also have this filter: "“UNSEEN ON " + DateTime.Today.ToString(“dd-MMM-yyyy”)” but still get all the read messages. How do I only get the unread messages?