From Change-Logs 5/9/2013
Like "previously locked quests", this seems to be something that BB have over-fixed.FIXES AND IMPROVEMENTS ... • Sometimes the icon indicating new messages was not showing up properly.
Lately, when I get the new mail icon next to my avatar, I look in my mail & read the latest delivery. Then I get an extra & erroneous new mail icon pop up when there is no new mail.
In a nutshell, the mail icon didn't always show up when there was new mail, now it's popping up when there is no new mail. (Can't decide if that's a fix, an improvement, or neither.)