Sometimes when I have a folder with a bunch of unread messages, deleting one that I've read (or don't want to read) causes the folder display of all posts to blank. If I move off that folder and come back, the messages are there. However, this is really annoying.
I'm pretty sure this is triggered by them being a filtered message, but I can't readily duplicate it.
Pretty sure this started happening a couple of versions ago, around a month or so. I figured it would be fixed, but that never happened.