God Complex - S8-E4
Character mistake: Spencer says that leg transplants are medically impossible, however, there was at least one documented successful double transplant performed a year before the season aired.
Factual error: The story is happening in Miami, Florida. Many shots show cars and the bad guys' truck with license plates in the front. In Florida cars don't have plates In the front.
Perennials - S8-E11
Deliberate mistake: In the outside shot of the unsub's motel in Pensacola, Florida, the sky is black as if someone behind the scenes tried to digitally remove part of the background in post, but did a really bad job.
Character mistake: When Reid realizes who the unsub is, he asks Hotch if he was introduced as "Doctor" or "Agent". As explained in the pilot (and in every episode since), the team has always introduced Reid as "Doctor", to make sure that the people they meet treat him with respect and don't just see him as a kid.
Suggested correction: I think the reason Reid asks for a clarification is because the unsub knew his name and title when he hadn't been formally introduced because this case was under special circumstances so the team wasn't being formal.
It has nothing to do with being formal. The mistake is saying the team never introduces Reid as "Agent Reid", so there's no reason to for Reid to even ask this question.
I think what they meant was that it would be assumed his title was agent, as he is a part of the FBI, but she addressed him by his correct title without any indication of his title being different to the others, which ultimately suggested that she knew Reid beforehand.
Magnum Opus - S8-E13
Continuity mistake: In the scene where you first watch the killer drain a victim's blood, the upper part of the glass jar is coated with blood, but when he puts it in the fridge this part of the jar is clear. On the other hand some of the jars in the fridge are still fully coated with blood, which shouldn't be as the blood had the time to gather at the bottom. (00:07:15)
Magnum Opus - S8-E13
Character mistake: Blake says the unsub must be a universal recipient blood type, AB pos, but they are talking about receiving plasma. The plasma universal recipient is O neg, the opposite of what it is for regular blood transfusions. (00:33:27)
Magnum Opus - S8-E13
Character mistake: At the end the murderer says Van Gogh only sold two paintings before he died. Van Gogh only had one of his paintings sell before he died.
Revealing mistake: When Agent Hotchner receives a text from JJ while interviewing the suspect, it is actually a screenshot. You can see Camera Roll in the upper left hand corner, "2 of 2" where JJ's name should be, and the Share/Play/Delete banner at the bottom. It is covered by Agent Hotchner quickly tapping on the screen to clear the banners. (00:16:15)
Continuity mistake: The unidentified subject is cutting a piece of flesh with a fork and a knife. The first shot shows him holding the fork with his left hand. His elbow is up, index finger straight, resting on the back near the head of the fork, the other four fingers wrapped around the handle. Next shot shows him elbow down, holding the fork with all his fingers wrapped around the handle.
Continuity mistake: When Wallace brings the snake home he takes it out of the tank and holds it. Between the constant shot changes the snake's position changes entirely.
The Inspired - S9-E2
Plot hole: At the beginning of the episode, PD let the suspect go (twin 1) because they accidentally arrested him for the crimes that his twin brother (twin 2) committed. Hotchner still wants to question twin 1, but a lawyer threatens Hotchner to not go near the wrongfully accused twin 1. However, in the previous episode, FBI and cops pursued twin 1 and twin 1 didn't pull over. It would be legal for twin 1 to be detained on a reckless driving or eluding the police charge.
Final Shot - S9-E3
Revealing mistake: As Reid explains human reaction time, near the end of it you can see a brunette woman get hit and fall to the ground, she hits ground with the back of her head and then, while supposedly been shot dead, moves her right hand in under her head.
Continuity mistake: In the video of the Chicago robbery they enter the building at 08:27 according to the timecode displayed, but they exit at 15:32. Seven hours is a very long robbery.
Continuity mistake: When the thief tries to steal the truck and the owner is beating him up, the passenger window behind the driver breaks. When his daughter later gets into the truck, very briefly the window is not broken. Then the next shot shows her in the truck, the window is broken again.
The Caller - S9-E10
Continuity mistake: At the beginning, a St Louis couple has reported their son missing. At the FBI briefing, the agents are told that the boy's mother tucked him in at 10:00pm. A few minutes later, we hear the radio call over footage of police at the home, and the dispatcher says "Last seen at 2100." That's 9:00pm, not 10:00pm. (00:03:00 - 00:05:00)
Audio problem: When Tabitha gets home, she takes her boots off and as she walks into the kitchen we hear the soft, padded sound of bare feet; when she closes the fridge and walks to the window, her footsteps indicate she has her boots on again.
Continuity mistake: While Reid's asleep in the hospital bed, Garcia places four Doctor Who figurines (one Dalek we don't see her place) on the overbed table - two Daleks, Matt Smith's Doctor, and David Tennant's Doctor. In the first shot Garcia's holding Smith's Doctor in her right hand and Tennant's Doctor in her left hand, but in the next shot those two figurines have switched hands.
Visible crew/equipment: When Hotchner, Callahan, JJ, and Rossi surround Frank's car on the private property, just after Callahan sees the leg on the seat, when she opens the passenger side door the reflection of the standing male cameraman/crew member is visible on the surface of the car, between the windows.
Other mistake: The age of the deceased Raymond Leu (35) shown in a death certificate doesn't match up based on year of birth (1948) and year of death (2014).
Continuity mistake: The original plane is a 747, (four engines on the wings, two aisles). The plane that Reid gets the plans for is a 727 tri-jet (three engines on the tail and one aisle, not wide body). The plane in the walk through by Reid is a wide body of some sort, but not a 747 (two aisles with three seats in the middle).