Help Wanted / Reef Blowers / Tea at the Treedome - S1-E2
Other mistake: During the show's introduction in Seasons 1-8, when the kids chant "SpongeBob SquarePants!" for the second time, the whole screen shifts slightly to the left. As a result, when the lyric, "If nautical nonsense be something you wish" is sung, the far right side of the screen is slightly mirrored. Note how, when any of the four boats are at the right side of the screen, they are briefly duplicated. (00:00:16)
Answer: I believe this is the Season 6 episode "Spongicus".