Hi, 

I just noticed with the last 3 users who signed up on my site via facebook that their usernames are the facebookid (eg: Facebook_10000XXXXXX)

I have not seen this behaviour with any other user so far. The only thing I did was change the details for the appId and secret to a new facebook app in the extensions authentications wizard but I don't see why this would change anything

Thanks for the help

Mark