Brady is probably hesitant to say what the specific issue is, since it was originally reported via Apple-internal channels. I'll make the call that it's worth saying what the bug actually is, since I'm sure external folks using Safari enough have experienced it. If a user is logged into Facebook, then under shipping Safari's default cookie policy, if they visit a Facebook connect site twice with a separation of an hour (or so), they will be logged out the next time they visit facebook.com. That's because Facebook attempts to refresh the login cookie fairly frequently, but the default cookie policy was preventing it from updating it. Note that it's not at all obvious why the logout happened - it took us an immense amount of debugging to narrow this down, starting with reports that just said "sometimes I randomly get logged out of facebook."
[^] # Re: Comment ça fonctionne ?
Posté par imr . En réponse au journal Plus intéressant qu'Apple : Mozilla sort Collusion. Évalué à 4.
Relax 3rd party cookie policy in certain cases