Audio problem: Right after Helga is standing behind the "ARNOLD" on the pavement, when she says "Hey Arnold", her lips move as if she's saying it slowly (this is fixed in the 4th season).
Arnold's Hat/Stoop Kid - S1-E3
Audio problem: When Harold says, "Hey, what are you, scared?" his mouth stays open for the last word. It never closes for the "d" at the end.
Door #16 / Arnold as Cupid - S1-E10
Audio problem: At the hat store, when Arnold says "Huh? What are you, nuts?", his lips don't move - but Gerald's do.
Abner Come Home / The Sewer King - S1-E16
Audio problem: When Arnold is playing chess with the Sewer King, Arnold jumps across the table and knocks the King over. This sequence appears to be sped up: the toilet crashes way after it is destroyed, and the King says "Noooooooooooo," yet his mouth never moves.
Suggested correction: The Sewer King's mouth does move, but it does say the line a little too late. However, the toilet crashing sound is exactly where it should be, and the scene is definitely not sped up.
Magic Show / 24 Hours to Live - S1-E18
Audio problem: Magic Show: During Arnold's magic show, the kids start chanting, "Make Helga disappear!" When Helga says, "Alright you bunch of clods," they stop, but their voices can still briefly be heard. (00:03:28)
Magic Show / 24 Hours to Live - S1-E18
Audio problem: Helga rides past Arnold in a bus and yells "24 hours until you die!" or something like that. Her mouth never moves- it just stays open in an evil smile.
Suggested correction: Although it's hard to make out, her mouth is moving when she says that. Also, she says "23 hours until you die!" not 24.
Save The Tree / New Teacher - S2-E1
Audio problem: New Teacher: When Helga gives directions to the kids to prank Mr. Simmons, she says, "Everyone know the drill?" and they all put their hands in. Arnold can be heard saying, "Alright," but he was never present in the scene. (00:13:47)
The Aptitude Test / Oskar Gets a Job - S3-E9
Audio problem: Oskar Gets a Job: After Oskar comes home after delivering the newspapers, as Arnold asks him, "Did you deliver the newspapers?", his mouth says, "Did you," but it never says, "deliver the newspapers?" (00:22:08)
The Aptitude Test / Oskar Gets a Job - S3-E9
Audio problem: In the comic book shop, Gerald says "Ho. Touche, sir." but his mouth doesn't move at all.
Helga's Show / The Flood - S3-E15
Audio problem: The Flood: When the kids go into room 315 looking for Mr. Simmons, Arnold calls out his name, and his mouth does not move. (00:20:24)
Helga's Parrot / Chocolate Turtles - S4-E6
Audio problem: Helga's Parrot: After Arnold accuses Lila of flicking his ear, as he says, "Well, somebody flicked it," his mouth only says, "Well." It never says, "somebody flicked it." (00:08:38)
Audio problem: When Arnold says, "It's almost like Dino left his whole life in my hands," as Grandpa responds with, "Not his whole life," his mouth doesn't move until the word "life." (00:06:58)
Monkeyman! / Buses, Bikes and Subways - S5-E1
Audio problem: Monkeyman!: When Gerald begins to tell the legend of Monkeyman, as he says the word, "Monkeyman," it looks as if his mouth only says the word, "Man," and it never says the "N" sound at the end. (00:01:50)
Monkeyman! / Buses, Bikes and Subways - S5-E1
Audio problem: Monkeyman!: When Gerald finishes telling the legend of Monkeyman, Stinky can be heard saying, "That was beautiful, Gerald," but his mouth doesn't move. (00:02:32)
Arnold Visits Arnie / Chocolate Boy - S5-E12
Audio problem: Arnold Visits Arnie: During the hayride, Arnold tells Hilda that she has a little straw in her hair. When he says, "Let me get it for you," his mouth does not move, it just stays in a smile. (00:09:14)
Grandpa's Packard / Phoebe's Little Problem - S5-E19
Audio problem: Phoebe's Little Problem: When Harold wets his pants at the end, Stinky can be heard saying, "Harold wet his pants," but in the shot, he is actually laughing. (00:11:39)