Continuity mistake: The age gap between Eric and Cory decreases as the series progresses. At the start of the show, Cory is in 6th grade and Eric is a high school sophomore, meaning they are four years apart, give or take a few months. By season 3, Cory is in 9th grade (confirmed by dialogue mentioning that Shawn, who is in the same grade as Cory, is 15 years old), and Eric is a senior, leading to an age gap of three years. The first episode of season 4 takes place a couple months after the end of season 3, with Eric and Cory returning from a summer Road Trip, but just two episodes later, Cory mentions that he is in 11th grade, while Eric is still barely out of high school, leading to an age gap of two years.
Clyde Bruckman's Final Repose - S3-E4
Continuity mistake: Clyde Bruckman commits suicide by placing a plastic bag over his head until he asphyxiates. However, when Mulder and Scully first discover him you can see in the shot just before Scully holds his hands that there is no plastic bag around his head (may only be visible in widescreen format). (00:42:55)
Continuity mistake: At the end of the episode, Odo has sent everyone affected by the telepathic matrix to a cargo bay. Sisko and O'Brien remove their com badges, throwing them aside before heading to the bay. After everyone is cured, Sisko straightens back up and, in the closeup, you can see that he has a badge on. In the next closeup, it's gone again.
Continuity mistake: In an interior shot of the detectives' vehicle, the car is a late 80s Chrysler (LeBaron or K-Car), obvious from the 'pentastar' logo on the steering wheel and the distinctive gauge layout. When the detectives walk away from the car, it is the homicide standard issue Chevrolet Cavalier.
Show & Tell - S6-E10
Continuity mistake: During a conversation with Diane, Jill says that her son is with his dad. In the conversation she calls the dad "Ken." In future episodes Jill's husband is called "Don." (00:03:55)
Continuity mistake: In an earlier season Caine takes a young Peter to a place in the temple and explains that his mother is buried there. However in the series finale he shows adult Peter a picture that someone took months ago and Caine tells Peter that the woman is his mother and he's going to find her.
Best Friends - S2-E9
Continuity mistake: Near the beginning when Colleen and Becky are talking to the boy, there is a boy walking in the background. When he loses his hat, he is behind the boy talking to the girls. In the next shot he is already behind the two girls, which is quite a great distance to cover in a split-second. (00:06:30)
Continuity mistake: One of the men attempting to kill Walker holds up his AK pattern rifle after one of his crew members is killed. If you look at the rifle, you can see that the safety is on and as a result, would not fire if he squeezed the trigger. Before and after this shot, the safety is seen in the off position. (00:22:55)
Ryuusui, Chimaera no Otoko - S1-E1
Continuity mistake: When Crosswords has the first attack of Chimera witnessed by Black Jack, his wife Sayuri runs to the fridge to grab the bottles. In the shot with the camera inside the fridge, there is a full complement of bottles in the bottom shelf, but in the other angle the right half of the shelf is occupied by glasses only. (00:09:15)