Factual error: Season 11, episode 2 ("Sugar"). When tracing the "Master Baiter" the detective says she can't trace the subject because "the HTML code is scrambled". There is no such thing as scrambled HTML, and on top of that HTML can never give away any information about a subject's location. Also, she can't get his IP address because it constantly changes. Yet, she does know from what exact wifi-spot he connected. If you get random IP-addresses, for instance by using random proxy servers, you can't pinpoint a location (which was of course why he used this technique).
Factual error: Season 9 episode 18 (TRADE): The scene where Pierson Bartlett is on the stand, he pulls a spoon out of his jacket. This would never be allowed. He wouldn't get through the metal detector with any metal that could be used as a weapon. He would either have to take it back to his car, or leave it at the security desk.
Factual error: The way that the drug Scopolamine is described is not accurate. It does not render the victim "unable to resist instructions". It can produce "twilight sleep", delirium and euphoria, but does not give anyone complete control over another person as depicted in the episode.
Factual error: When sergeant Benson is in the bathroom alone after it has been declared clear she looks at her phone to see a picture message from Lewis of the little girl he has tied up. She then texts him back saying "where are you" but at the top of the screen it says unknown as if the sender has blocked their number, so it would be physically impossible for sergeant Benson to reply to this message.
Factual error: When Stabler's son Dickie is trying to join the Army, Dickie's recruiter tells Stabler that he can join at 16 with parental consent. This is incorrect, you have to be at least 17 to join the U.S. Army even with parental consent. Even if you could join at 16, the consent papers that Dickie bought to Stabler at the end of the episode can't be signed without a recruiter or notary public present and signing the papers at the same time. This is to prevent cases where a parent who had a change of heart can claim they didn't sign and to prevent 17-year olds from enlisting without consent by forging their parents' signatures.
Factual error: The episode took a lot of liberties to further the plot when Amelia Albers was arrested by the Coast Guard in ADA Barba's office. While the story mentioned a real controversial military pamphlet on how victims should respond to a sexual assault, at the time the episode took place the military was under a massive investigation over sexual assaults by Washington, was being publicly criticized for a lack of assault victim support, and had a bill going through Congress to make it easier for victims to report their attackers. There is no way any military prosecutor would have been given clearance to charge Amelia with adultery or fraternization while the men she was accused of sleeping with were charged with gang-raping her. Doing so would bring a lot of unwanted bad press as well as a congressional investigation on the Coast Guard that would almost certainly want to know why they are attempting to cover up a rape by charging the victim instead, especially when the rape victim was an admiral's daughter.