I thought it was too, but if you look more closely, you can tell it was EJ’s old apartment, which he gave to Steve and Kayla who in turn gave it to Adrienne, but since we have no reason to see Adrienne’s apartment, I guess the set people just gave it to Stephanie and Nathan.
I’m willing to bet that Philip and Melanie will probably end up Lucas’ old apartment down the hall from Chloe and Daniel, which will be the perfect setup for the who’s the daddy storyline.