Factual error: On the way to the Hamptons, Castle's car is driving on the left side of the road, even though they're in the US (where people drive on the right side of the road). (00:03:10)
Continuity mistake: Castle and Beckett are talking about the case in the precinct and his coffee runs out. Beckett offers to go refill the mug. She grabs his white mug in her right hand. In the next shot, it is now in her left hand. A blue mug is in her right hand instead. (00:05:15)
Plot hole: When Ryan asks Beckett where Castle is, Beckett says something like "I don't know. I thought that the death of a bridesmaid would be right up his alley." and Ryan replies "Probably heard the word "wedding" and got cold feet." Only problem is, how could Castle have known that? He was duct-taped to a chair at the time Beckett called and couldn't answer the phone. We see Beckett right after he falls on the table and we don't see her leaving a voice mail or send a text message so he couldn't have known, especially since he asked "So, bridesmaid huh?"
Factual error: When Castle and Beckett go to talk to the victim's assistant, there is a chalk outline on the floor where the body was discovered. Although it's common in police dramas, chalk outlines are not actually police procedure, because it contaminates the crime scene. (00:08:40)
Continuity mistake: When Castle and Beckett go to question Jeffrey McGuigan, Beckett raises her badge twice: once while the camera is on Guy Wilson, and a second time when the shot cuts and the camera is on Stana Katic. (00:25:15)
Character mistake: When the private investigator shows Castle and Beckett the VIP Liaisons website, "Liaison" is misspelled "Liason." (00:17:40)
Continuity mistake: When Beckett, Esposito and Ryan interview the fruit stand vendor, he states that he saw a bronze Mercedes drive by, to which Esposito replies, "That's Castle's car." In the previous scene at the car crash site, Ryan asks Esposito to check the back corner of the car for damage, which is silver or gray, not bronze, in color. (00:04:35)
I, Witness - S7-E13
Continuity mistake: When Castle and Beckett are in bed, their pillow cases are dark and patterned. When Beckett wakes up to find Castle gone, the pillow cases are white. (00:30:00 - 00:30:40)
I, Witness - S7-E13
Revealing mistake: When Castle answers his phone at the start of the episode, his phone is on the lock screen instead of in call mode.
Smells Like Teen Spirit - S6-E15
Factual error: German bearer bonds would never have English writing on them, and furthermore instead of just saying "German bearer bonds" the company or other entity that issued them would be named.
In the Belly of the Beast - S6-E17
Continuity mistake: After Beckett gets back from her assassination assignment, she washes up in a bathroom and places the gun she was given in her front waistband near her stomach. Then she goes to meet Lazarus (Vulcan Simmons) in the basement, who realizes she's Beckett. When she pulls out the gun, she reaches behind her back to get it. (00:27:25 - 00:31:00)
Home Is Where the Heart Stops - S1-E7
Continuity mistake: After the two talked to the victim's daughter, Castle buys Beckett a soda. The way he holds the can as he hands the soda to her changes between consecutive shots.
Continuity mistake: Jennifer Beals' blouse mysteriously changes from white to blue while they are in the CIA secret bunker prior to heading out for the final confrontation.
Nanny McDead - S1-E2
Other mistake: When Castle is reviewing the footage of the nanny in the elevator, he observes there is a five second time difference between the two time codes. But there's actually a difference of seven seconds. (00:25:15)
Plot hole: The security camera images of Castle kissing Kyra on the roof are completely inexplicable. The angle at which the images are taken are near enough identical to the angles at which the rooftop scene were shot. There were no pillars, poles or high walls for a security camera to be attached to at those particular angles, and certainly nowhere a photographer could hide, so where did the images come from?
Suggested correction: Beckett had Kyra followed, because she was a suspect. The photos were taken by the person following her.
Flowers for Your Grave - S1-E1
Continuity mistake: When Castle finishes talking to Gina about his new book that's due, he raises his champagne flute with his right hand, but when he actually imbibes the alcohol, the flute is in his left hand. (00:04:25)
To Love and Die in L.A. - S3-E22
Visible crew/equipment: At the pool, after Beckett makes a stunning entrance from the water, a white reflector screen is seen on Ganz's sunglasses. (00:31:40)
Continuity mistake: When Beckett and Castle are talking about the failed sting on Rathborne, Beckett's hand jumps back and forth from gripping her coffee mug by the handle in the close ups to the bottom in the wide shots. (00:36:45)
