Messages being sent twice

Sending a message to a facebook friend at Outlook.com or through the Messaging app on Windows 8/RT results in the message being sent twice. The duplicate message doesn't show up on facebook.com, however. I reached out to MSFT but so far no one has been able to help. Looking at the reviews for the Messaging app in W8, a bunch of people are having this problem. All is fine on WP8. Is anyone else having this issue?