Factual error: Nick tells fellow vampire Aristotle, "You still owe me for that time at the Battle of Hastings." Nick was brought across in 1228, or so the intro told us every week. The Battle of Hastings, as any British school kid knows, was fought in 1066, over 100 years before Nick's mortal birth. (00:29:30)
Days of Future Past: Part 2 - S1-E12
Factual error: When Gambit is inside his mini-jet after escaping from Bishop and Wolverine, his radar screen says "Washington D.C." but the graphic above it is Washington state.
Factual error: Batman is in Japan and tracks down Kyodai Ken by using Caller ID, which returns a seven-digit "555" number. Telephone numbers in Japan have 8 digits.
The Tale of the Whispering Walls - S2-E7
Factual error: Betty Ann is supposed to be telling this story on a Leap Year night with a full moon. While it's necessary for the plot, the most recent Leap Year with a full moon was in 1972, and is calculated to happen in 2048 next.
Factual error: When Charles Barkley says "Welcome to the NBA" after dunking on Mark, the ceiling shown above Barkley is way too low to be the ceiling for Haas Pavilion at UC Berkley where the game is being played. It only appears to be about 30 feet high.
Factual error: In many episodes, cars which are said to be owned by a character have a Certificate of Fitness on their windscreen. Private passenger vehicles in New Zealand under 3.5 tonnes have a Warrant of Fitness, not a Certificate of Fitness. This means these cars are most likely rentals.
Framing of the Shrews - S3-E29
Factual error: Alison is in her office in Hong Kong and takes a telephone call from Brooke, calling from D&D in Los Angeles. It is daylight outside Alison's window and the office is busy around Brooke. There is a 15-hour time difference between Hong Kong and Los Angeles; it is not possible to have normal business hours in both locations at the same time. (00:14:00)