"Internally, isn't MS deploying these builds before they're released? I'm sure MS staff are forwarding meetings all the time, or is MS not eating their own dog food anymore."
Ouch. Of course Microsoft installed and used the updates themselves before releasing the code to us. That's the "right" thing to do, so of course Microsoft did that. Nobody would be dumb enough to have their customers experience the update issue before they have had time to iron things out internally. Honda engineers and company employees actually drive the cars before they sell them. Of course Microsoft dog foods all of their own products. Ballmer probably has this exact same issue going on right now when he forwards calendar items too.
They have to be at least on CU1 right now because that is their mandated support model for other companies as well. Once the new CU is released, only it is supported and the previous version. That means RTM Exchange 13 is not supported anymore and nobody at Microsoft is still running it.
Exchange team, that's correct information, right? Someone back me up here.