Comment 5 for bug 317819

I believe this bug is still valid. I experience it in 9.10, it is also reported here:

http://readlist.com/lists/suse.com/suse-linux-e/37/189573.html

I can provide more information: it does not fix itself if you click away from the folder and back again. I am using IMAP. I believe that the title is inaccurate; there are in fact unread messages in the folder. When this problem occurs, you can remove the unread filter and use next or previous unread message commands to reach the messages. For me, they show up as normal, but they have an invalid date ("?"). One idea is that this is an issue with the index of the messages: I noticed that as you sort by date or click the unread filter on and off whilst having a date-based sort, the messages with invalid dates will move position. Presumably they cannot be ordered consistently because of the nature of the sort algorithm.