I thought I was the only one that noticed, the a user pointed it out and now I verified it happens here, too.
Send a PM and request a Read Receipt, when the receipt comes back it says
Your private message to sportbikes about 'Re: Calendar Birthday Intergration' has been read.
Well... I'm "sportbikes" so the message was actually to another user... not me?
I think it is grabbing the wrong field in the body portion??