Today I have a new message on the seller app and in my browser. Since I was unable to find it on my seller app I turned to my desktop.
My new un-responded to/ unread message was sent April 5, 2013.
I have no words.
xoxo, Katy
@KisforCalligraphy: Have you checked the applicable CSV file to make sure that is not also showing up as a new thread? We have had new messages attached to ancient threads but have not yet had the experience of an old message in an old thread showing up as a "new message".