Why does my Yahoo! Mail display a totally different message after I click on a certain message?

It's been a recurring problem that has been happening with me for around 3 months now or more! The problem is simply as follows: whenever I click on the subject of a certain e-mail message (say in INBOX, for example), a totally different e-mail message is displayed in the next screen (say from SPAM folder, for example). Sometimes, the message that is usually displayed instead of the intended message is usually the one that I've just read...I mean the one I read immediately before clicking on this new message that is never displayed. Surprisingly, the only way to sort this out is to right-click on the target message and ask windows to display it in another window or tab. But I don't like this option...and I'm worried that this problem is happening with me because of a bug or virus...any ideas or suggestions??? Best regards...