Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Patrick goes up to the man with a briefcase holding a pad of paper and a pencil. In two shots, the pad and pencil Patrick was holding disappears.
Squidtastic Voyage/That's No Lady - S4-E15
Audio problem: In "That's No Lady", Mr. Krabs throws a megaphone behind him, but there is no sound of it clattering after him throwing it.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", there is a place card on the table Mr. Krabs is sitting at. When he puts a sheet over the table, the spot where the card was, doesn't bulge.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Patrick has some type of glasses, which he takes off his face and holds in his hand. In the next shot, they disappear.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Spongebob has a tray with two lemonades and gives one to Patrick. In two shots, the tray and the two glasses of lemonade disappear.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "Squidtastic Voyage", Squidward drinks many bottles of soda to try and get Spongebob and Patrick out of his stomach. Two shots later, these bottles all disappear without anyone touching them.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In 'Squidtastic Voyage", Spongebob uses a remote to open the doors of the submarine. This remote disappears in the next shot.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Squidward is standing at the register, holding a newspaper. When it cuts to "Patricia", and back to Squidward, Squidward isn't holding the newspaper anymore.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Patrick runs through Spongebob's wall, leaving a Patrick-shape in his house. Patrick pushes a bit of Spongebob's house, which disappears in the next shot.
Answer: I believe this is the Season 6 episode "Spongicus".