Today i associated my account with meta.stackoverflow.com, but username is not transferred. It just says 'user164226'. But when i associated webmasters.stackexchange.com (and many others), username was correct. Is it a bug on meta?
If you go to StackOverflow, and then go to your profile page, and then to the accounts tab, then at the bottom of the page, you should see a button saying "Copy your Stack Overflow profile to all Stack Exchange accounts"; now, if that's not going to have any adverse affects for you, try that - does that fix it?