Now that there's a new release, I was waiting for the email with the update notice. But that didn't happen.
It did update Twenty Twelve, but not Core.
I thought that it might have been Beta Tester, but it didn't update after I switched to Point Release Nightlies.
And I got the same problem on my other site. So I have the same problem upgrading from both 3.4.2 and 3.5-RC6.
Also... I think the problem exists since 0.8.2, because I haven't had upgrade notices about RCs and nightlies since that update.