Born Again Krabs (aka A Penny Saved) / Safety Freak (aka I Had An Accident) - S3-E17
Continuity mistake: I Had An Accident: When SpongeBob leaves his house to save Patrick and Sandy, he leaves the door open behind him, but in the next shot, the door is suddenly closed. (00:22:25)
Born Again Krabs (aka A Penny Saved) / Safety Freak (aka I Had An Accident) - S3-E17
Other mistake: Born Again Krabs: When the Flying Dutchman gives Mr. Krabs the choice of either taking SpongeBob or all the money in his pocket, the Flying Dutchman says he has 62 cents, and Mr. Krabs says he will take the money. In the next shot of SpongeBob, his right leg is missing. (00:10:35)
Other mistake: In the credits, Tom Kenny, Bill Fagerbakke, and Rodger Bumpass are credited for playing SpongeBob, Patrick, and Squidward. However, Patrick and Squidward's names should be "Patar" and "Squog," and "SpongeGar" should be shown along with SpongeBob's name (SpongeBob makes a small appearance near the start of the episode). (00:22:32)
Character mistake: Near the end of the second Patchy the Pirate segment, the narrator says, "What will SpongeBob do with fire?" However, the character's name is actually "SpongeGar." (00:14:29)
Chocolate With Nuts / Mermaid Man And Barnacle Boy V - S3-E11
Audio problem: Chocolate With Nuts: When SpongeBob and Patrick walk out of Barg'N-Mart with the chocolate bars, SpongeBob says, "Fancy living, here we come," but his mouth doesn't move until the shot changes mid-sentence. (00:02:10)
Krabby Land / The Camping Episode - S3-E19
Continuity mistake: Krabby Land: When Mr. Krabs sticks his head out of his office near the start, the door to his office is missing, but then it appears a moment later. (00:01:42)
Welcome to the Chum Bucket / Frankendoodle - S3-E2
Continuity mistake: Frankendoodle: When SpongeBob pranks Squidward by pulling the dollar away from him, Squidward's monocle falls on the ground, but when the mustache flies away, the monocle has vanished. A chain on the monocle also appears in one shot, then disappears. (00:15:47)
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)
Continuity mistake: When Patar heats the squished crab in the fire, it's in his left hand. But in the next shot when he eats it, it's in his right.
Wet Painters / Krusty Krab Training Video - S3-E9
Continuity mistake: When Mr. Krabs Gets Home, there is a light switch by the door, but in the next shot there is a sign instead.
Krab Borg / Rock-a-Bye Bivalve - S3-E8
Continuity mistake: Rock-a-Bye Bivalve: When Patrick gets home from the party after midnight SpongeBob is angry, and as Patrick walks out in the interior shot the front door is wide open on the inside of the home, but in the next exterior shot the front door is wide open on the outside of the pineapple.
Mermaid Man and Barnacle Boy IV / Doing Time - S3-E1
Continuity mistake: Mermaid Man and Barnacle Boy IV: When SpongeBob runs into the kitchen with Mermaid Man's secret utility belt, the door swings open facing away from the grill, but when Squidward demands to know what's going on in the kitchen, the door opens the opposite way.
Nasty Patty / The Idiot Box - S3-E4
Continuity mistake: Nasty Patty: After the police officer cancels his Krabby Patty order, when he tells his partner they got a call about "two ghouls burying a stiff," Krabs' office door is missing.
Nasty Patty / The Idiot Box - S3-E4
Continuity mistake: Nasty Patty: When Krabs pushes SpongeBob out of the kitchen telling him to pour on the charm for the health inspector, the door swings opens at the left side, but when SpongeBob goes back to the kitchen to order one of everything, that door opens the opposite way, then the switch happens again.
Club SpongeBob / My Pretty Seahorse - S3-E12
Continuity mistake: My Pretty Seahorse: After Krabs tells SpongeBob the restaurant is not a place for a live horse, when SpongeBob walks out with the seahorse the swinging door to the Krusty Krab's kitchen opens in the opposite direction than previous shots.
As Seen on TV / Can You Spare a Dime? - S3-E5
Continuity mistake: As Seen on TV: After SpongeBob shouts about the grand finale he tosses all the food at the hungry crowd, and as they all happily exclaim, "Krabby Patties," there is only one door to the right of Squidward's order station in this shot, though there should be two doors.
As Seen on TV / Can You Spare a Dime? - S3-E5
Continuity mistake: As Seen on TV: The front door to Mr. Krabs' office is a solid door with an anchor on the exterior side of the door, but in a few shots the office's front door has a porthole window like other doors in the restaurant.
Krab Borg / Rock-a-Bye Bivalve - S3-E8
Continuity mistake: Krab Borg: The door to Krabs' office has a porthole in many shots, but after Krabs burns his eyes he rushes out of his office into the eating area, and when he runs past Squidward and SpongeBob the office door is the normal solid door, with an anchor on the exterior side.
Chocolate With Nuts / Mermaid Man And Barnacle Boy V - S3-E11
Continuity mistake: Chocolate With Nuts: While SpongeBob and Patrick are selling chocolate, the elderly female's door opens at the left, but after Patrick claims their chocolate will make you live forever, the door is open the opposite way.
Answer: I believe this is the Season 6 episode "Spongicus".