Mermaid Man and Barnacle Boy III / Squirrel Jokes - S2-E4
Other mistake: Squirrel Jokes: At the end of SpongeBob's second act, as he tells the crowd, "Thank you, you've been a wonderful audience," he opens his eyes briefly, and they are coloured yellow instead of white as they should be. (00:20:14)
Mermaid Man and Barnacle Boy III / Squirrel Jokes - S2-E4
Other mistake: Squirrel Jokes: Near the end of SpongeBob's second act, he tells the crowd to give a big hand to Sandy, but to clap slowly, because she's a squirrel. Right as he says, "She's a squirrel," the holes on the bottom left of his face disappear mid-shot, then reappear. (00:20:09)
Survival of the Idiots / Dumped - S2-E8
Other mistake: Survival of the Idiots: When SpongeBob and Patrick first try to escape the tree dome, SpongeBob tries to open the door, then says that the door is slippery and frozen shut. SpongeBob's reflection is shown in the ice on the door, but it is not backwards; note the holes on his face. (00:08:43)
Big Pink Loser / Bubble Buddy - S2-E3
Audio problem: Big Pink Loser: After SpongeBob gets a load of awards delivered to him at the Krusty Krab, Patrick gets frustrated and says, "Why can't I do anything right?" But the audio briefly cuts out as he says, "Why," so it sounds like, "Wh - can't I do anything right?" (00:05:09)
Survival of the Idiots / Dumped - S2-E8
Other mistake: Dumped: When SpongeBob first gets mad at Gary for spending time with Patrick, he picks him up and walks away with him. In the close-up of Gary as SpongeBob is holding him, SpongeBob's sleeve is coloured yellow instead of white as it should be. Additionally, the purple spots on Gary's shell are a lot bigger than usual. (00:17:18)
Survival of the Idiots / Dumped - S2-E8
Other mistake: Dumped: When Patrick agrees to join SpongeBob and Gary in their game of tag, SpongeBob tags him, and as SpongeBob walks away from him, his right collar leaf turns red for a frame, then the space between his tie and left collar leaf turns brown for another frame. (00:13:32)
Survival of the Idiots / Dumped - S2-E8
Audio problem: Survival of the Idiots: After SpongeBob and Patrick unfreeze the door with their breath, Sandy sees them from her window and says, "Oh look, it's SpongeBob and Patrick," but if you look closely, her mouth is not moving. (00:11:48)
It Came from Goo Lagoon - S9-E7
Continuity mistake: The apparel of the fish at the top of the water-skiing pyramid at the start changes between shots.
No Free Rides / I'm Your Biggest Fanatic - S2-E10
Continuity mistake: No Free Rides: When SpongeBob's boat is falling towards the police car, SpongeBob rips off the top part of Mrs. Puff's ski mask, leaving the bottom half of it on her. In the next shot, it disappears, and her regular outfit is shown. (00:11:12)
Patrick SmartPants/SquidBob TentaclePants - S4-E8
Continuity mistake: SquidBob TentaclePants: When the mixed-up SpongeBob and Squidward come out of Sandy's matter transporter, Squidward's arm is on the left, and SpongeBob's arm is on the right. Later on at the Krusty Krab, in the shot after Mr. Krabs tells both of them, "Alright, that's it!", we can see that both arms are SpongeBob's, when the left one is supposed to be Squidward's. (00:17:42)
Bubblestand / Ripped Pants - S1-E1
Continuity mistake: Bubblestand: When SpongeBob comes out of his house at the beginning, he leaves his front door open. Later on, when Patrick's rock opens up, the front door to SpongeBob's house is completely missing. Then, when SpongeBob hands Patrick the bubble wand, the door is back, and it is now closed. Finally, when SpongeBob and Patrick walk into the house later on, the door is open again. (00:02:30)
Bubblestand / Ripped Pants - S1-E1
Character mistake: Ripped Pants: During the opening credits, Paul Tibbitt's name is misspelled as "Paul Tibibitt" (it is spelled correctly the second time it is shown), and Mark O'Hare's name is misspelled as "Mark O'hare." (00:11:54)
Hall Monitor / Jellyfish Jam - S1-E7
Continuity mistake: Hall Monitor: When SpongeBob sees the open window to the house, the window is opened to the left. When the two fish run out of the house after SpongeBob scares them, the window is opened the opposite way, then reverts back in the next shot. (00:05:19)
Chocolate With Nuts / Mermaid Man And Barnacle Boy V - S3-E11
Character mistake: Chocolate With Nuts: When SpongeBob and Patrick go to the first house, SpongeBob tells the man, "Good afternoon, sir." However, when they go to the second house, he says to the man "Good morning, sir." (00:02:52)
New Student Starfish / Clams - S3-E14
Continuity mistake: New Student Starfish: SpongeBob shows Patrick the Good Noodles board when they enter the classroom. Then when Patrick is trying to tell the class his name, the number of stars on it change, and the name "Rich" appears on it, which wasn't there before. Later on, when SpongeBob and Patrick are in detention, the names on the board are completely different in some shots. (00:02:48 - 00:11:24)
Big Pink Loser / Bubble Buddy - S2-E3
Revealing mistake: Big Pink Loser: When Patrick says, "Why can't I do anything right?", and starts hitting his broom on the floor, the drinks that are supposed to be on the customers' tables are instead layered behind them. (00:05:18)
The Thing/Hocus Pocus - S4-E16
Continuity mistake: The Thing: When Squidward is riding his bike on the road, he hits a cement truck, and gets covered in cement. He tries to get out of it, and a shot later, the location suddenly changes from the road to a green hill. (00:04:05)
Whatever Happened to SpongeBob? (WhoBob WhatPants) - S5-E18
Continuity mistake: Near the beginning, SpongeBob picks up Gary, and some of his slime falls on the floor. When he hugs him and breaks his shell, the slime is gone. (00:01:56)
Have You Seen This Snail? - S4-E3
Other mistake: When Gary comes back at the end, when Gary meows and SpongeBob says, "Yeah, like that," the tears in his eyes disappear for about half a second. (00:22:50)
Bummer Vacation/Wigstruck - S4-E14
Other mistake: Bummer Vacation: When SpongeBob says, "You're right, Gary. It is unhealthy to think of the Krusty Krab while I'm on vacation," his legs are missing. (00:05:55)
Chosen answer: You need to provide a little bit more information to be able to answer a question like this. In what region is it not being shown? I see it being replayed here in Australia fairly frequently. As for a general reason, there does not appear to be any for why it specifically might have been taken off the air in any country or region. Like any show certain episodes can sometimes not be replayed for long periods for unknown reasons.
Lummie ★