Al Sah-Him - S3-E21
Character mistake: Diggle turns to Nyssa and says "I think what she's trying to say is, Oliver would never do anything to hurt you, Felicity," incorrectly addressing Nyssa as "Felicity." (00:14:50)
Restoration - S4-E3
Factual error: Felicity apparently extracts DNA from the tooth of one of Damien Darhk's men. She then realises that the DNA lacks "half of the genetic markers" by looking at an optic microscope. Skipping the fact that this sentence makes absolutely no sense whatsoever, you certainly cannot analyse genetic markers by simply looking a tooth with an optic microscope. (00:11:05)
Suggested correction: No science behind this statement.
What is it supposed to mean?
Visible crew/equipment: When Slade brings the drink in the forest (referring to Billy Wintergreen), you can see shadows of people walking upstairs in the background behind a big white curtain. (00:07:30)
Suggested correction: It's not a crew member, it's wind.
Left Behind - S3-E10
Visible crew/equipment: During a flashback with Oliver and Maseo, they are on a rooftop trying to break in to the building next door by means of the pulley system on the bow. Maseo is shown lining up a shot with his sniper and in the background one can see a crew member's face looking over his shoulder. (00:13:30)
Suggested correction: There are other ARGUS agents with Oliver and Maseo. That is one of them.
Suggested correction: When Diggle is walking away from Felicity, he is still talking to her but it looks like he is talking to Nyssa.
Stephen Edmonds 1
People have already tried to correct this mistake. It is valid. In the scenes prior, Nyssa says Oliver will do what it takes to kill her and Oliver says "tonight, Nyssa Al Ghul faces justice." Nyssa is there to bring the team the news that Oliver is going to try to kill her. Felicity says "Oliver wouldn't", meaning Oliver wouldn't try to kill Nyssa. Diggle says "I think what she's [she being Felicity] trying to say to say is that Oliver would never do anything to hurt you" [you being Nyssa whom Oliver is going to try to kill]. He is meant to say "Nyssa." Otherwise the entire line means Nyssa or Laurel are there to convince Felicity that Oliver would never do anything to hurt Felicity.
Bishop73