If you're looking at your sent PMs, they all show what you wrote, but they look like they were written by who you sent them to.
For example, if all your outgoing PMs look like they're from NGene, it's because you've only sent PMs to NGene.
I think it's a good feature, actually. Think about it, if you're in your "sent PMs" folder, obviously they're all from you. What good does it to you to know that they're from you? So instead it uses the name/avatar/etc of the person you sent it to, so you know who it's to