This slip-up is in the episode titled "Logan Miller." About twenty minutes or so into the episode you see Peggy behind a desk. You only see her but you hear Miranda in the background say something like, "so Logan works on the Railroad," Then, Peggy tells her "No, he worked in a lumber yard," (or something similar) but when the camera moves away from Peggy, Miranda is not there, only Declan. And no matter how much you look around, Miranda is not there. (It helps if you want to tape it to pause it or rewind it to check it out).