There's a pretty major bug with this, actually. If you do check with John about the message, then leave the police station, go to the apartment with Sully, then leave the apartment and return to the police station, Erica says 'I need to check with John about this message' AGAIN, and obviously since you've already done so, you can't check with him again. You then cannot leave the police station no matter what.
Yes, that's the same problem I encountered.
There are other times this 'repetition' bug creeps in ('Agent Davies' sending an email to someone in order to elicit a certain response for example)
but not in a game-breaking way.
Annoying bugs aside, I really enjoyed this episode.