Other mistake: Right at the start, as they're crashing, the computer narrates their rapidly-dropping altitude in feet. But the "altitude" dial we're shown is in metres. Most noticeable as they cross the 3,000 mark, when the computer voice and the height say/show the same number at the same time, despite the different units. 3,000m would be more like 9,000 feet, or 3,000 feet would be more like 1,000m. (00:03:20)
Other mistake: Episodes 4 and 5 of season 1 aired noticeably out of order. In episode 4, "The Nanny," Alex's former Nanny, Rosalba, comes to work at his podcast company, and its name, "Ajana," is mentioned a few times. But episode 5, "The Mother-in-Law," starts with the company unnamed; over the course of the episode, Alex learns of the concept of "ajana," the unknown, from his mother-in-law and chooses it as his company's name.
Character mistake: The firefighters state that the acronym for CPR is ABC for Airway, Breathing, Circulation. This is very outdated as in 2010 the American Heart Association changed the recommendation to CAB for Compressions, Airway, Breathing following evidence that compressions first in CPR saves more lives.
Plot hole: The FBI is looking for a "very tall" guy who has been identified as such by various witnesses and by their own expert due to the entry angle of a fatal bullet wound - 6'5" at least. They send Elena into a bar near the end of the show to meet the Albanian perp who when he arrives is barely average height.
Character mistake: When the bodyguards enter elevators, they always enter last; they should be entering first to ensure it is secure. This is particularly visible in the hotel where the elevator can stop on any floor and Special Protection Branch does not have complete control of it as an express.
Factual error: A thief has stolen 75 million dollars. He runs out with two large duffel bags. All US bills weigh a single gram. This means that $1,000,000 in $100 bills - the largest bills in circulation - weighs around 10 kilograms, or a little over 22 pounds. $75 million would be 1,650 pounds. No way this could be carried in two duffel bags.
Visible crew/equipment: During the strobe lighting at the very end of series three, with Faustus Blackwood seemingly releasing something evil, it is noticed that during the flashes, it is leaving after effects, showing the shape of the equipment that make the strobe lighting. (00:58:00 - 01:00:00)
Character mistake: Dan makes a reference to the movie "Planes, Trains, and Automobiles" (the movie he's planning on the family to watch). He starts a sentence saying "by the time John Candy says 'those aren't pillows'." John Candy did not say that line in the movie - Steve Martin did.
Other mistake: All the Greek name variants are used over the Latin ones - including even "Odysseus" over the more familiar "Ulysses" (who is the same person). However when the story of Actaeon comes up, it's suddenly the goddess "Diana" that he saw. But all the gods have their Greek names, so that should be "Artemis." (As indeed is used in episode 2). (00:39:35)
Visible crew/equipment: Right before Anissa and Tavon are attacked by Khalil, the shadow of a camera can be seen on the ground in the bottom right corner of the screen as they approach the path.