Disharmony - S2-E17
Other mistake: When Harmony spills her pig's blood on the keyboard, the computer shorts out, and the monitor flickers off, but the mouse cursor is still visible. (00:25:35)
Disharmony - S2-E17
Other mistake: At the very end, as Angel walks out the door he reflects in the panes of glass on the door. (00:42:10)
Other mistake: In the episode "The Shroud Of Rahmon," when Angel changes into his vampire face, his teeth don't change into fangs. (00:33:55)
Other mistake: Both times we see Lindsey shaving, once before his hand transplant and once after, his reflection in the bathroom mirror isn't in fact a reflection. He is wearing a bracelet on his left wrist, but in the mirror it is on his right wrist.
Other mistake: Later in the day when Cordy has recovered a little and is cleaning, Angel says something about seeing a reflection in the picture. We hear Cordy say, "What do you want," but the subtitles say, "What do you what?"
Answer: Due to his epiphany, Angel basically had the 'true darkness' he worked so hard to reattain ripped away from him, like his soul was after sleeping with Buffy.