Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: In "Mermaidman Begins", the first time it shows Ernie microwaving the popcorn, there are 21 buttons on the microwave. In a later shot, there are now 24.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: In "Mermaidman Begins", the scientist experimenting on the ants knocks over the jar containing five ants. In the next shot, there are eight ants on the floor.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: In "Mermaidman Begins", the camera goes up one story to show a scientist. On the poster next to him, it shows various molecules and particles. In the next shot, the word "science" appears on the poster.
Karate Star - S8-E2
Continuity mistake: Spongebob is mopping the floor when a customer walks in the tell him about Patrick chopping everything. Two shots later, the mop and the water on the floor disappear.
Continuity mistake: Spongebob is looking up at the roots that are bouncing above him. In the first shot, there are only three above him. In the next shot, it shows more roots, with Spongebob standing under four.
A Flea in Her Dome / The Donut of Shame / The Krusty Plate - S5-E11
Continuity mistake: In "The Krusty Plate", Spongebob finds that one plate has a brown smudge on it. After an attempt to clean the plate, he lifts it up and the smudge is now a light shade of green.
Giant Squidward/No Nose Knows - S6-E7
Continuity mistake: In "Giant Squidward", Squidward goes to spray his wilting kelp with fertilizer and sets down a watering can right next to him. When the kelp goes back to normal in the next shot, the watering can disappears and is not seen again.
Hall Monitor / Jellyfish Jam - S1-E7
Continuity mistake: In "Hall Monitor" when SpongeBob is pretending to be the "open window bandit," you can see a red piece of coral outside of the house that he is about to break in to. When he jumps through the open window, frightens the people inside, and they run out of the house, the red piece of coral is gone.
Jellyfishing / Plankton! - S1-E3
Continuity mistake: In "Jellyfishing" when Squidward comes home in the bed thingy, the king jellyfish hovers above him. At first, Squidward is facing his house. But in the next shot, he is facing the road. When he replies "Ow" he is facing his house again.
Jellyfishing / Plankton! - S1-E3
Audio problem: In "Plankton!" when Mr. Krabs steps on the krabby patty, he replies with "this ain't no ghost" his mouth doesn't move at all.
Krab Borg / Rock-a-Bye Bivalve - S3-E8
Continuity mistake: The scene in episode Rock-a-Bye Bivalve where SpongeBob and Patrick start arguing about working for Junior at Patrick's house, SpongeBob is not inside the house. While SpongeBob is staring down at Patrick, his head is sticking out of the top of the hole in the ground. Once SpongeBob jumps in the top of the hole is way past their head.
Giant Squidward/No Nose Knows - S6-E7
Continuity mistake: In "No Nose Knows", Patrick is trying out his new nose. He passes through a cloud of perfume sprayed by a fish in front of the perfume shop. In the next shot, the fish and the perfume shop are gone.
Gullible Pants/Overbooked - S6-E19
Continuity mistake: In "Gullible Pants" when Mr. Krabs is about to exit the Krusty Krab, he looks at his watch, which disappears in the next shot.
SpongeBob's House Party (aka Party Pooper Pants) - S3-E10
Continuity mistake: When SpongeBob is locked out of his house, he digs a hole to try and get in. This hole doesn't exist the next morning.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: In "Fools in April", Squidward put some paper towels in his ears to block out the noise of Spongebob's laugh echoing throughout the Krusty Krab. He covers his ears, and in the next shot, the paper towels are missing and not in his hands.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: In "Fools in April", Gary is sleeping next to his food bowl in the first shot, with Spongebob's bed nowhere to be seen. After hearing Spongebob's voice, Gary wakes up. In the next shot, Gary's food bowl is sitting in front of Spongebob's bed post.
Help Wanted / Reef Blowers / Tea at the Treedome - S1-E2
Continuity mistake: In "Tea At The Treedome" Patrick is seen lying on his rock, and the wooden stem thingy on his house is to the right of his house instead of the middle, and is a lot taller too.
Rodeo Daze/Gary in Love - S7-E15
Continuity mistake: At the end of Rodeo Daze, the bullfrog bursts the bubble and everything lands on the ground in its "real" state, except there's no Squidward. We are told he's an octopus, so he wouldn't be one of the fishes that we see.
Jellyfishing / Plankton! - S1-E3
Continuity mistake: In "Jellyfishing" when SpongeBob is playing Squidward's clarinet he says "Sorry, my lips are a little dry." Then he starts licking his lips. In one shot, the clarinet disappears from SpongeBob's hands. Then it reappears in the next shot.
SB-129 / Karate Choppers - S1-E14
Continuity mistake: In "Karate Choppers" when SpongeBob sticks his arm through Sandy's phone, Sandy sticks SpongeBob's hand through the other end, then Sandy puts the phone down and SpongeBob's hand immediately disappears.
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 ★