Arnold Saves Sid / Hookey - S2-E7
Continuity mistake: The kids' teacher in this episode is Miss Slovak, who was their teacher in the first season, but in the first episode of this season they have a new teacher, Mr. Simmons.
Suggested correction: Other than the few episodes that take place during a specific time of year; these episodes are not meant to be taken in chronological order. Just roughly in the same 4th grade school year.
Arnold Saves Sid / Hookey - S2-E7
Continuity mistake: The clock in the police station looks like it says it's after 5:00, but school is in session.
Freeze Frame / Phoebe Cheats - S2-E8
Continuity mistake: The next night, Phoebe's bed clothes switch back and forth between her nightgown and her dress.
Mud Bowl / Gerald Moves Out - S2-E9
Continuity mistake: When Gerald catches his little sister destroying his cassette tape, the book she is wrapping changes color from blue to green. (00:12:30)
The High Life / Best Friends - S2-E10
Other mistake: Best Friends: When Arnold walks across the table during the fashion show, a small chunk of the spotlight vanishes mid-shot. (00:22:13)
The High Life / Best Friends - S2-E10
Continuity mistake: Best Friends: During the fashion show, in the close-up of Arnold showing off the antennas on his costume, the curtains that he came out of are missing. They are also missing in the shot after Arnold tells Gerald, "Just smile and move, okay?" (00:22:22 - 00:22:50)
The High Life / Best Friends - S2-E10
Other mistake: Best Friends: When Gerald is first revealed during the fashion show, the curtains are transparent. They are never transparent in any other shot. (00:22:26)
The High Life / Best Friends - S2-E10
Deliberate mistake: In "The High Life", there is a scene where Stinky submerges his head in a tank of water. He delivers the line, "Gee willickers, it's still ticking", and everyone somehow understands what he is saying with his head underwater.
Suggested correction: Nobody responds to what Stinky says, so there's no reason to assume that everyone understood him.
Steely Phil / Quantity Time - S2-E12
Continuity mistake: The digits on Arnold's clock get bigger and change shape while he's talking to Grandpa.
Steely Phil / Quantity Time - S2-E12
Continuity mistake: Chinese Checkers is supposed to be with ten pieces per side, not six.
Eating Contest / Rhonda's Glasses - S2-E13
Continuity mistake: In the last scene, Rhonda is seen through the bus's rear window as sitting in the back of the bus - but just before that, she's talking to the girl with the frizzy hair in a seat closer to the front.
Helga's Boyfriend / Crush on Teacher - S2-E14
Revealing mistake: Helga's Boyfriend: When Arnold walks up to Helga to tell her that Stinky loves her, he asks if he can talk to her about something, and in the shot of Helga, there is a line at the bottom of the screen going through her legs, cutting them off. (00:08:04)
Helga's Boyfriend / Crush on Teacher - S2-E14
Continuity mistake: Crush on Teacher: When the kids are playing baseball and Miss Felter drives by, Harold starts walking to the side of the road, and Helga is standing on the road. In the next shot, Harold is already standing to the side of the road, and Helga is standing on the sidewalk. Helga's mask also disappears. (00:12:42)
Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Crush on Teacher: When the kids are playing baseball and the baseball hits Arnold, as he says, "I'm fine, Miss Felter," his eyelids are not colored in. (00:13:02)
Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Crush on Teacher: When Arnold and Gerald are walking to school and Arnold gets distracted by the birds and flowers, as he says, "Look at the flowers," his eyelids are not colored in. (00:14:37)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Continuity mistake: Harold's Bar Mitzvah: In the beginning, when Stinky asks Harold if he wants to play stickball, there is no wristband on his arm. Harold says he has to go do his lessons, and in the next shot, a wristband appears on Stinky's arm, then disappears. Later on, when Harold comes out of the synagogue, his wristbands are back on his arms. (00:12:03)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: In the credits, actor Elliott Gould's name is misspelled as "Elliot Gould." (00:22:59)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: In the credits, Justin Shenkarow is credited twice for voicing Harold. (00:22:59)
Coach Wittenberg / Four-Eyed Jack - S2-E16
Continuity mistake: Coach Wittenburg's anchor tattoo changes color from red to purple in between shots.
Suggested correction: No, his tattoo is always red.
Coach Wittenberg / Four-Eyed Jack - S2-E16
Factual error: When the kids are bowling for the first time, the placement of the pins is wrong, and when Arnold is bowling there are 11 pins.