Revealing mistake: The scene is set in Boston, MA, USA, but at a murder location, a European-style circular power outlet is visible through the glass doors at the bottom of the concrete wall. (00:01:20)
Continuity mistake: When Danny and Ward meet Joy in her new place, Ward says "who was it who said I was being childish?" Danny is in the background, holding the folder cover open with his left hand. Shot cuts as he speaks, and his hand's suddenly on the pages with the folder cover hanging down loose.
Ashes, Ashes - S1-E6
Continuity mistake: Spoiler! At the end of the episode, after Elektra decapitates Alexandra, the blood pattern on her changes changes when she turns around and asks "any questions?" Most noticeably more blood on her forehead and two streaks down her chin that suddenly appear. (00:49:10)
Revealing mistake: The flipped ambulance at the beginning of the episode does not have a drive shaft. (00:03:09)