FarmerBob/Gary and Spot - S12-E1
Continuity mistake: In "FarmerBob" when SpongeBob is taken to Old Man Jenkins' farm, after that, the next shot when he is stretched about 50m tall by a bag of potatoes, the tie is missing. (00:00:50 - 00:01:25)
Character mistake: In "Sandy's Nutty Nieces" SpongeBob gets thrown and flung at Sandy's treehouse, then when he falls down and Sandy opens the door, SpongeBob's shirt color changes. (00:01:25)
Answer: I believe this is the Season 6 episode "Spongicus".