Episode #2.3 - S2-E3
Character mistake: DS Maxwell comes to Katy's house to interview her but when he introduces himself he says "DI" Maxwell.
Character mistake: When Collier is meeting all the 4400s at the reunion, Shawn calls Isabelle Maia by mistake. (00:31:10)
Character mistake: Upon finding the Spanish flu virus missing, Hardison freaks out about it killing 50m people 100 years ago, saying it would be even more deadly today due to the higher population. There's no reason to think so - the death toll in 1918 was massively exacerbated by the aftermath of WWI. Not to mention today we have vaccines, plus most deaths then were actually caused by bacterial pneumonia, which today is easily treated with antibiotics.
The Night of the Skulls - S2-E13
Character mistake: There are seven mourners dressed in black surrounding Gordon's casket - three on each side and one by the funeral officiator (who is the disguised Gordon). Later in the scene when West is talking to the disguised Gordon, Gordon says, "How do you like that - six mourners..." (00:05:20 - 00:07:10)
Character mistake: The team identifies a blue Lexus fleeing the scene of the murder, but later in the show OA says to Maggie that they've located the black Lexus.
Character mistake: Sam describes the books as being from "pre-Biblical lore" and then says they are written in Aramaic. Aramaic was a language during New Testament Biblical times and didn't exist in pre-Biblical times i.e. prior to 4000 B.C.E.
Suggested correction: I believe he meant the book "contained" pre-biblical lore.
Character mistake: The voice tells Tom that the alarm deactivation code is 47223. However, when Tom enters the code subsequently to deactivate the alarm, he only enters "4723." You can tell he doesn't enter a fifth digit because the keypad chimes each time a digit is entered.
Episode #5.3 - S5-E3
Character mistake: The chief baddie spells definitely as definately.
Character mistake: Nathan suggests to Dwight and Audrey that maybe he should shut down the meeting of troubled people. As chief, he should know he has no authority to stop citizens from assembling.
Character mistake: A police officer describes a murder weapon as a revolver. It is an automatic pistol.
Second Time - S2-E13
Character mistake: When Kiera is begging one of the Freelancers to send her back she says she could "prevent Liber8 from ever coming to 2077." She should have either said "coming to 2012" or "leaving 2077."
From Agnes - With Love - S5-E20
Character mistake: Using a Texas Instruments TI-89 Titanium, the seventeenth root of 9,000,355,126,606 is 5.781163783, which means the first prime number greater is seven.
Champion vs. Creator, Part II - S1-E27
Character mistake: Pegasus says his toon world cannot be penetrated, but that is not true since it's a magic card, so any card that destroys magic cards can destroy it. Furthermore, monster special effects can also destroy it.
Character mistake: Joe called Cruz a Sergeant First Class (E-7), which is a US Army rank. It was established in Season 1 that Cruz is in the US Marine Corps, so she would be a Gunnery Sergeant (E-7). (00:19:48)
Character mistake: Voice on the radio says a 39-year-old with a gunshot to the left shoulder; however, Will was shot in the right shoulder. (00:40:13)
Thrill Kill - S5-E1
Character mistake: At the end, when Dylan exits the prison, there's a sign that reads "No Tresspassing" on the prison gate. However, "No Trespassing" is the correct spelling. (00:42:35)
Character mistake: When Rich refers to the film showing Davis (decades ago), he figures they were in "Asia... Mongolia or somewhere." However, the film cannister had "Tibet, 1937" written on it - important enough to show the audience, but not for the character to read? (00:40:25)
Dedication - S1-E7
Character mistake: When they show the helicopter containing Alpha team, it is a Bell 206 JetRanger, and the sound effects match it, but Brown says "This is the first time I'm on a Huey." The Huey and JetRanger look and sound nothing alike. (03:25:00)
Character mistake: The note Six hands the "access man" misspells the word "receipt" as "reciept." He's supposedly a "think tank" genius, so really should be able to spell better than that. (00:27:30)
Episode #3.4 - S3-E4
Character mistake: DS Miles while in the chocolate shop tells Ana to go with "DCI Riley." Riley has the rank of DC, not DCI.