Sleep Tight - S3-E16
Continuity mistake: Right before Holtz and his men arrive at the hotel, Angel arranges three of Connor's toys in his cot. One of them is a teddy bear which he places in the middle of the cot. But once Holtz and his men arrive, the teddy bear is suddenly at the far end of the cot resting on the pillow.
Visible crew/equipment: When Angel is fighting the demon, you can see an obvious camera and two hands in the bottom right corner. (00:27:10)
Trivia: In the opening credits there is a shot of a girl standing alone on the corner of a street. This was taken from the Buffy episode "Anne", when Buffy was staying in Los Angeles.
Answer: Everybody including Angel saw her. After helping them and then being left alone to talk to Angel, Cordelia says that the Powers That Be let her come back one more time to help them. After Angel gets a call saying that she died, he realises that it was her spirit that was helping them the entire time.