Helga's Show / The Flood - S3-E15
Continuity mistake: Grandpa's rubber raft got much bigger between the time he left the greenhouse and the time he arrived.
Crabby Author / Rich Kid - S3-E17
Continuity mistake: In "Rich Kid" Lorenzo is introduced as a new student, but he was in a previous episode titled "Arnold's Room."
Suggested correction: Other than the few episodes where a specific time of year is taking place; these episodes are not meant to be taken to be shown in chronological order. Just roughly in the same 4th grade school year.
Suggested correction: I agree with the other correction, but it's also worth noting that in the production order, "Rich Kid" was made before "Arnold's Room." They were just aired out of order, just like many of the other episodes.
Girl Trouble / School Dance - S3-E18
Continuity mistake: Besides the fact that when Helga is sharpening her pencil, the desk arrangement changes, one of the students visible when she looks at Arnold is... Helga. This happens because the shot is taken from the episode "Helga's Love Potion."
School Play - S3-E19
Continuity mistake: When Arnold is getting his lunch, his tray is empty. When he picks up the cup of green stuff and Helga gets mad at him, a milk carton appears on his tray. (00:00:29)
School Play - S3-E19
Continuity mistake: When Mr. Simmons tells the class about the Romeo and Juliet play, the projector has four legs. When the class is watching the presentation, it has three legs. Then when the kids leave the class, it has four legs again. (00:02:38)
School Play - S3-E19
Continuity mistake: When Mr. Simmons tells the class that they are welcome to come and try out for the play, there is no cap on the projector. When the kids start to leave, a cap appears on it. (00:03:18)
School Play - S3-E19
Continuity mistake: In the auditorium, when Mr. Leichliter claps and starts talking to Mr. Simmons, the location he is standing in changes three times. (00:05:19)
School Play - S3-E19
Continuity mistake: In the auditorium, when Mr. Leichliter says, "Indeed, it is I," there is no exit door on the wall to the left of him. In the next shot, an exit door appears on the wall. Later on, in a wide shot of the auditorium, the door is gone, and there are now double exit doors on the perpendicular wall. (00:05:22 - 00:05:57)
School Play - S3-E19
Continuity mistake: Lila's collar is gold throughout the episode. When the girls audition for the part of Juliet and Mr. Simmons says that they were all very good, her collar is white, and her gold button is missing. Then when Mr. Simmons says Lila will be the third understudy, her collar is gold again, but her button remains missing. Later on, when Mr. Simmons announces Lila will take the role of Juliet, her collar is white again, and her gold button is missing again. (00:08:46 - 00:14:26)
School Play - S3-E19
Continuity mistake: When Helga tries to convince Lila to drop out of the play, as she says, "What about that crazy costume you have to wear?", Lila's gold button is missing. It's also missing when Lila says, "I'm sorry, Helga, you're mumbling." (00:15:42 - 00:17:06)
Full Moon / Student Teacher - S4-E1
Continuity mistake: Full Moon: When Principal Wartz tells Arnold to see him every day after school for the next four weeks, the words on his office door are yellow. About a second later, they change to red, then back to yellow. (00:02:57)
Full Moon / Student Teacher - S4-E1
Continuity mistake: Full Moon: When Arnold leaves the school at the beginning, he is carrying a green book. A few seconds later, the rectangle on the cover changes to white, then back to green. (00:03:14)
Full Moon / Student Teacher - S4-E1
Continuity mistake: Full Moon: Throughout the episode, Harold's eyes change from yellow to white during a few consecutive shots, as well as mid-shot.
Big Gino / Jamie O. In Love - S4-E2
Continuity mistake: During "Jamie O. in Love," in the very last scene, Jamie drives up in a car whose front license plate reads "Killer." When they leave, the back license plate reads "Killr." There is no space for a letter to have possibly fallen out (not that a letter can fall off of a license plate).
The Beeper Queen / Oskar Can't Read? - S4-E4
Continuity mistake: Oskar Can't Read?: When Oskar comes home at the end, Ernie and Mr. Hyunh are standing on Arnold's left. As they walk inside the house, they are on Arnold's right. (00:22:36)
Love and Cheese / Weighing Harold - S4-E7
Continuity mistake: Love and Cheese: When Arnold asks the man at the CheeseBall Toss for three tries, Eugene in the background has black skin and a red shirt, like Gerald. His shirt is also red in a later shot when Arnold is trying to knock the bottles down. (00:05:52)
Love and Cheese / Weighing Harold - S4-E7
Continuity mistake: Love and Cheese: When Arnold is trying to knock the bottles down and Lila gives him a flirty look, her collar turns green for one frame. (00:06:12)
Love and Cheese / Weighing Harold - S4-E7
Continuity mistake: Love and Cheese: When the sign for the Built-To-Hurl is first shown, it is spelled with a hyphen between "To" and "Hurl." When the sign is shown again, that hyphen is missing, then reappears a moment later. (00:07:19)
Love and Cheese / Weighing Harold - S4-E7
Continuity mistake: Love and Cheese: When Helga drills the hole into the back of Arnold and Lila's boat, she drills it into the side of it, but when it's shown from inside the boat, it's in the center. (00:09:06)
Love and Cheese / Weighing Harold - S4-E7
Continuity mistake: Love and Cheese: Helga drills a hole in the back of Arnold and Lila's boat, but in all the following shots where the back of the boat is shown, the hole is not visible. (00:09:07 - 00:10:31)
