Revealing mistake: In "Not Normal" when SpongeBob says "Hmm. This video tape should help," his left arm is missing. (00:01:25)
Best Day Ever/The Gift of Gum - S4-E20
Revealing mistake: When Squidward says "I suppose if you haven't fixed my clarinet, the concert would have been a bust", Sandy's tail is the same color as her suit.
Revealing mistake: At the end of "Wormy", Patrick's eyes are missing.
The Secret Box / Band Geeks - S2-E14
Continuity mistake: When SpongeBob is sneaking to Patrick's house, Squidwards house is missing.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Continuity mistake: In "Pranks-A-Lot" when Sandy flies out of her dome in an escape pod to Texas, she leaves a big hole on top of her dome. In the next shot, it's gone. Very noticeable mistake.
Hall Monitor / Jellyfish Jam - S1-E7
Continuity mistake: When SpongeBob asks Squidward to play his clarinet better, he is wearing his night shirt which is purple, but in the next shot he is wearing his normal shirt which is brown.
Jellyfishing / Plankton! - S1-E3
Continuity mistake: The words "Total Control" constantly appear and disappear from the controlling device in Spongebob's brain.
Mermaid Man and Barnacle Boy IV / Doing Time - S3-E1
Continuity mistake: In the scene where the guard pulls Mrs. Puff out of the rock yard, her hat is red, then blue, then red again throughout the cuts in the scene.
Sandy's Rocket / Squeaky Boots - S1-E8
Continuity mistake: In "Squeaky Boots", Mr. Krabs starts hearing squeaky sounds everywhere. Then he goes mad, and says he took the boots from SpongeBob. In this point, notice of the restaurant floor's color. Mr.Krabs somehow lifts the whole restaurant but we can still see some floor (where Krab is). Notice that now the color of the floor has changed.
Revealing mistake: At the beginning of Rock Bottom, when the bus pulls up in front of Patrick and SpongeBob, right before Patrick steps up onto the bus, SpongeBob's right arm is missing and it suddenly appears as he starts moving.
Chocolate With Nuts / Mermaid Man And Barnacle Boy V - S3-E11
Revealing mistake: In one scene with Spongebob, Patrick, an old lady, and her almost dead mom, in one part Spongebob has no holes on his face. There is also a light-colored spot near Patrick's mouth.
Enemy In-Law/Mermaidman and Barnacleboy VI: The Motion Picture - S4-E7
Other mistake: Plankton's phone doesn't have a 0 button on it.
Revealing mistake: Near the end of "Rock Bottom", when SpongeBob arrives back to Bikini Bottom, SpongeBob's pineapple is animated differently from the other buildings. It looks like it was cheaply tacked on in post production.
Dying For Pie / Imitation Krabs - S2-E6
Revealing mistake: In the episode "Dying For Pie", you can see Mr. Krabs' legs disappear when Squidward says, "But you can't pay me enough to act brotherly on that guy!"
Your Shoe's Untied / Squid's Day Off - S2-E2
Character mistake: In "Squid's Day Off", a wide shot shows Mr. Krabs exiting the hospital, except the building says" ENEREENCY" instead of "EMERGENCY."
Continuity mistake: When Plankton is telling Karen, "There's a whale in the laboratory," he is jumping up and down with his arms in the air, but in the next shot, his arms are suddenly down at his side.
Continuity mistake: When SpongeBob accidentally reveals the location of the formula, Plankton drops the feather he is holding and lands in front of him. The feather remains on the floor, but when Pearl walks into the kitchen, the feather has suddenly vanished, and reappears in front of Plankton in the next shot.
Continuity mistake: When Mr. Krabs and SpongeBob are standing in front of the bomb after it lands but doesn't go off, the clock inside Mr. Krabs' office can be seen from the kitchen. The time on the clock is 5:00, but in the next shot, the time on the clock is suddenly 3:00. The bomb is then revealed to be a mechanical hand, and the time on the clock is now 5:00 again.
Patrick-Man!/Gary's New Toy - S9-E2
Continuity mistake: In "Patrick-Man", in the scene after Mrs. Puff gets arrested, the guy that SpongeBob serves the krabby patty to in the Krusty Krab is not wearing a T-shirt until the guy says "Lets hope Patrick Man doesn't confiscate this one," then he is seen wearing a white T-shirt. (00:08:00)
Help Wanted / Reef Blowers / Tea at the Treedome - S1-E2
Revealing mistake: When Spongebob uses his binoculars, his teeth turn yellow for one frame.
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 ★