The Dropout - S2-E1
Character mistake: When Greg was in his room talking to his parents, he said that Joe DiMaggio, Mickey Mantle and Yogi Berra never went to college. Joe DiMaggio attended Yale University, Mickey Mantle attended the University of Oklahoma and Yogi Berra attended Montclair State University.
Suggested correction: DiMaggio dropped out of high school and worked odd jobs before playing semi-pro ball. His son, Joe DiMaggio Jr attended Yale for one year. Mantle was offered a scholarship to Oklahoma to play football, but he never went. He started playing semi-pro ball at the age of 17. Berra dropped out of school after the 8th grade and then signed with the Yankees when he was 18 (but served in the military before playing). Montclair State University gave Berra an honorary degree in 1996.
The Dropout - S2-E1
Other mistake: When Greg is in the kitchen getting ready to leave for the baseball game, there is a number 53 on the back of his jersey. In the following scene at the baseball park, there is another man with his back turned throwing practice balls, who also has the number 53 on the back of his jersey. It is clear that it is not the same person.
Continuity mistake: The home number Mike dials in the men's bathroom to check on the kids, is very different than the home number Carol dials in the ladies restroom. (00:18:30 - 00:18:56)
The Un-Underground Movie - S2-E4
Continuity mistake: During the filming of Greg's movie, Mike is in the stockade when Peter dumps the box of "snow". When the family sits to watch the film, Mike is released from the stockade by Carol before the snow is dumped. (00:17:45 - 00:20:10)
Continuity mistake: The horse figurine and telephone on the table next to Greg are not in the same positions from shot to shot. (00:07:15)
The Treasure of Sierra Avenue - S2-E7
Visible crew/equipment: The set lights are reflected in Greg's beach ball in what is supposed to be an outdoor scene. (00:20:35)
Continuity mistake: Cindy's notebooks keep changing in number and color during Peter's confrontation with Buddy. (00:21:30)
Visible crew/equipment: A shadow of a boom mic is visible moving across the brick wall just as Alice starts to punch Mike in the stomach.
The Not-So-Ugly Duckling - S2-E9
Continuity mistake: When Jan comes home and tells her parents that Clark didn't notice her at school, she's wearing a white blouse with a floral design and a red ribbon in her hair, but when she gets to her bedroom and accuses Marcia, she's wearing a striped blouse and a light green hair ribbon. Then when Jan talks to Greg she's wearing a green tee shirt and a dark green ribbon, but when she asks permission to go to the store she's back in the striped blouse and light green ribbon.
Continuity mistake: When Cindy goes downstairs to ask "isn't anyone coming up to say goodnight?" or something similar, when Alice is talking to Mike and Carol about Sam not coming over, Cindy is wearing her pyjamas. She then gets in trouble and goes straight back up to her room and she is suddenly dressed in jeans and a top - her hair has different hair ties in it too.
Audio problem: Tiger is heard barking as he runs down the stairs, but it's obvious the dog isn't barking at all. (00:06:05)
Deliberate mistake: While Bobby's parakeet is flying around downstairs, before the bird settles down on the TV set there are two closeups of Bobby which are flipped shots, note the furniture and Bobby's PJs. (00:07:00)
Deliberate mistake: When Bobby's at the treehouse the second time for his initiation into the club, there's a boy already up in the treehouse, and after Peter takes the birdcage from Bobby's hand, the next closeup of the boy in the treehouse is a flipped shot, note the wood boards. (00:08:25)
Revealing mistake: When Peter is on the trampoline, instead of saying "Peter," Carol says, "Go get 'em, Chris!" and a few minutes later the same thing happens after Cindy has a turn alone, you can hear Greg say "Why don't you give it a try, Eve?" (00:18:10 - 00:19:50)
Continuity mistake: When Bobby attempts to climb the treehouse for the second time, he climbs to the very top and looks up in fright. From his POV we see he has two more wooden bars to climb, despite being at the top a split second ago.
Confessions, Confessions - S2-E12
Continuity mistake: When the boys are playing ball in the bedroom, Greg has on a pair of dark jeans. When they go downstairs to see the broken vase, he is wearing a normal pair of blue jeans. (00:01:30 - 00:02:30)
Confessions, Confessions - S2-E12
Continuity mistake: When the vase gets broken, it's easy to see that one large piece flies off the chest of drawers onto the floor. And when the boys look down at the broken vase from upstairs, three pieces are on top of the chest of drawers. But Greg - seen later trying to fix it - says something to the effect of "Good thing it only broke into three pieces." So what about the piece that flew off onto the floor? (00:02:00)
Confessions, Confessions - S2-E12
Continuity mistake: The vase broken by the ball is obviously not the same one dropped by Carol at the end of the episode. The first one was thicker and darker. (00:02:15 - 00:24:05)
Confessions, Confessions - S2-E12
Visible crew/equipment: The shadow of what appears to be a moving camera can be seen moving across the pieces of broken vase. (00:02:35)
Confessions, Confessions - S2-E12
Revealing mistake: At the start of dinner, in the wide shots we can see the table and chairs directly on the carpet. When Carol notices the leaky vase and calls for Alice, in the wide shot as Alice approaches the table, now there's plastic sheeting spread across the carpet under the table, as well some visible tubing under the table, presumably for the water stunt. (00:05:45 - 00:08:15)