nope, it's way more subtile than that.
www is not hardcoded, but CB RC4's cookie management try to adapt to mismatches between live_site settings and current url as well as they can.
All those cases are imho now treated correctly.
Only case which can't be dealt with are buggy cookies remaining from previous builds on wierdly setup domains.
So now that cookies are cleaned, i believe all should be well.
Please let us know if you are able to reproduce after your cookies cleanup.
I'm considering this bug as being part of the past, hopefully.