Compromised - S1-E9
Character mistake: When she and OA meet Marshal Ackerman, Maggie is somewhat surprised to learn Damon Cruz was a federal witness. As a federal agent herself, Maggie surely would know that the Marshals Service's mandate includes the witness protection program.
Parenthood - S4-E10
Character mistake: Chimney tells Mrs. Lee, "Eddie and I are managing OK," but he should have said "Maddie and I..."
Episode #5.3 - S5-E3
Character mistake: The chief baddie spells definitely as definately.
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.
Angel of Mercy: Part Two - S1-E4
Character mistake: When Lenore Osgood is speaking on the phone with Charles Wainwright about killing Dr. Hanover, she mispronounces "Larynx" as "Lar-nix."
Character mistake: A police officer describes a murder weapon as a revolver. It is an automatic pistol.
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 #1.1 - S1-E1
Character mistake: In the subtitles, Halcrow mentions a German company as 'Unternehme'. The right spelling of this German word is 'Unternehmen'. (00:46:35)
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)
Episode #1.1 - S1-E1
Character mistake: Abigail says that Max is very unusual as a university graduate who has joined the police, and it can't possibly have been his first choice of career. In fact, well over one-third of British police recruits have been graduates since long before Max would have joined.
Character mistake: Jaden tells Damon that because of Elemental Hero Flame Wingman's ability, he will lose life points equal to half his destroyed monster's attack points. This is incorrect, as Damon will actually lose life points equal to the full attack points of the destroyed monster. He has used this card multiple times throughout the series, so this isn't a mistake he should have made. (00:18:25)
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.
Six Forgotten Warriors Chapter 4: The Six Fight Again - S5-E5
Character mistake: When the Red Skull reemerges from the vortex, he sees Chameleon and acknowledges him as his stepson. However, only moments before this, Kragov explicitly stated that the Chameleon was more like an adopted son to the Red Skull.
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)
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.
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)
First Blood - S12-E9
Character mistake: Sam points out Elk Mountain, but there is no Elk Mountain in Rocky Mountain National Park.
The Night of Miguelito's Revenge - S4-E12
Character mistake: The store window's sign says, "Denver Mercatile" rather than "Mercantile."
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: When Collier is meeting all the 4400s at the reunion, Shawn calls Isabelle Maia by mistake. (00:31:10)