The best thing that you can do about this issue is to contact the Yahoo! Mail team - I don't believe they monitor these forums so the contact form might be best. For contact information for the Yahoo! Mail team, please see this thread: http://developer.yahoo.net/forum/index.php?showtopic=1716. They'll be able to take care of any issues.
Jonathan LeBlanc Senior Software Engineer Yahoo! Developer Network Twitter: jcleblanc