Tutoring Torvald / Gerald Comes Over - S1-E13
Continuity mistake: Arnold switches from his left hand to his right hand when taking the test.
Suggested correction: I don't believe it is ever established whether Arnold is left or right-handed in the series. Without confirmation; he may very well be part of the ambidextrous population that uses both. I used to write with both hands myself in school.
I do believe he is ambidextrous. In "The longest Monday" he is using chop sticks with his right hand. Many other episodes he uses his left hand to write.
Except the mistake is saying he switches hands in between shots during the test. Not that one episode he's left handed and the next he's right handed. Yes, the teacher was shown for about 1-2 seconds before the switch happened. But these mistakes should be considered valid as an actual mistake in animation rather than to suggest to the audience that for no reason whatsoever, Arnold switches hands to finish the test, and only does so when not seen.
I'm ambidextrous myself, and I often switched hands when taking tests. It was very useful for preventing hand cramps. It only takes a couple of seconds to switch the pencil to the other hand, so I don't see why Arnold can't do it within that span of time too.
Love and Cheese / Weighing Harold - S4-E7
Continuity mistake: Lila was pretty much entirely underwater in a "standing" position when Arnold rescued her, how come suddenly the water only reached her knees?
Love and Cheese / Weighing Harold - S4-E7
Trivia: In 'Weighing Harold', when Arnold is in the comics store, there are comics in the background referencing other Nickelodeon shows, "Catdog" and "Spongebob Squarepants." The former had aired almost exactly a year before this episode did ('Catdog' premiered on 4/4/1998 and this episode on 4/7/1999). The later aired about a month after this episode.
Freeze Frame / Phoebe Cheats - S2-E8
Continuity mistake: Phoebe Cheats: After Phoebe reads the poem from her book, she sets the book back against the lamp, and it is closed. Then when Phoebe gets up out of her chair, the book is suddenly open. (00:14:05)
Girl Trouble / School Dance - S3-E18
Other mistake: Girl Trouble: When Phoebe says she has costume designs for the Mandans, the Chinook, and Sacagawea, Gerald says, "I could have sworn it was Sacagawea." Then, there is a shot of Helga and Phoebe, but there is a problem with this shot. What we're supposed to see is Helga and Phoebe sitting in their seats at their side of the table. Instead, the background is of Arnold and Gerald's side of the table, while Helga and Phoebe are shown in front of the table, which doesn't make sense. (00:02:31)
Other mistake: Ms. Perfect: After Lila answers Mr. Simmons' question about the inventor of the telegraph, as Phoebe says, "But I knew that," the book on Nadine's desk is overlapping the back of Phoebe's chair. (00:14:07)
Helga Blabs It All / Harold the Butcher - S3-E1
Continuity mistake: Helga Blabs It All: After Helga successfully snatches the message tape, when she rushes out of Sunset Arms the front door is missing its handles, but one handle reappears when Campfire Lass and other girls chase after Helga.
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Continuity mistake: Hall Monitor: When Principal Wartz tells Helga she cannot volunteer again, he removes the "revered badge" and its black crossbody strap from Helga. Helga then selects Phoebe as the next hall monitor. When Phoebe joins them on the stage, Helga is again wearing the crossbody strap with the badge in the wide shot, but it's gone in the next shot as Wartz places it on Phoebe. (00:02:10)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: Hall Monitor: During detention, the class helps Phoebe realise how much she has changed. When Helga wipes the window so Phoebe can see her reflection, in the first shot, Phoebe's reflection is not backwards as it should be. (00:10:45)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: Hall Monitor: When Helga chooses Phoebe to be the new hall monitor, as Phoebe starts walking to the stage, she is briefly layered behind the boy sitting behind her, and she is layered over Joey and the boy sitting next to him. (00:02:31)
Runaway Float / Partners - S2-E20
Other mistake: Runaway Float: After Nick talks about redesigning the parade float, Bob asks the kids who wants to ride on the float. Arnold then tells them it's great the way it is, and when the kids start saying, "Me! Me!", there is an animation glitch where part of Robert's head and hands get stuck in the air for about a second. (00:06:01)
Back to School / Egg Story - S4-E8
Other mistake: Back to School: After Principal Wartz tells Phil he will find a classroom for him, it cuts to a shot inside Mr. Simmons' classroom. If you look at Sid in this shot, the lower half of his body is cut off. Phoebe's right foot is also layered over him. (00:03:58)
Helga's Locket / Sid and Germs - S5-E7
Other mistake: Helga's Locket: When Helga climbs to the top of the boarding house and looks at Arnold and Grandpa through the window, as Arnold tells Grandpa, "It's embarrassing and weird," Helga's left sleeve is incorrectly coloured pink instead of white. (00:09:02)
Monkeyman! / Buses, Bikes and Subways - S5-E1
Continuity mistake: Buses, Bikes, and Subways: Helga wears a watch on her right arm throughout the episode. However, when Helga approaches Sheena's uncle Earl and wakes him up, her watch is missing, then reappears when Earl's boat sinks. It disappears again when Helga comes up from the water, then reappears a moment later. (00:18:59)
Save The Tree / New Teacher - S2-E1
Continuity mistake: New Teacher: Arnold's classroom door vanishes from its door frame in various shots, then the door reappears in its proper place. That door's doorknob also switches between the right side of the door and the left side a few times.
Sid's Revenge / Roller Coaster - S3-E8
Other mistake: Sid's Revenge: When Sid is telling the police officer that he killed his school principal, Arnold's pants are the same colour as his skin, and his hat is not coloured in. (00:09:13)
Curly Snaps / Pre-Teen Scream - S3-E6
Other mistake: Pre-Teen Scream: When the kids are sitting on Arnold's stoop in the beginning, there are two shots where Arnold's pants are the same colour as his skin, giving the sense that he has no pants on. (00:12:03)
Arnold's Thanksgiving - S3-E14
Other mistake: When Arnold is in his room putting on his costume, his reflection in the mirror shows his buttons on the left side of his clothes. Then, when Arnold answers the door, his buttons are on the same side; the reflection was not reversed. (00:09:26)
Parents Day - S5-E6
Continuity mistake: During the flashback, when little Arnold says goodbye to his parents, in the next shot of Stella and Miles, the bag's strap is slung over his dad's left shoulder as a crossbody, but mid-shot, the strap switches to his right shoulder with the bag on the opposite side. (00:14:30)
Parents Day - S5-E6
Continuity mistake: When Grandpa enters and exits Arnold's bedroom, the door opens the opposite way in various shots, with the doorknob on either the left or right. Additionally, the light switch beside the door appears and disappears, between shots.
