The Peruvian Puff Pepper - S3-E2
Other mistake: Drake and Josh find the monitor in Megan's room. After they reveal the normal wall and the family leaves, Megan hits the button behind the picture to show the monitors. However, when Drake and Josh find out that Megan entered the salsa competition, they storm into her room, but the button is still revealed in the background.
Other mistake: When Sportacus jumps out of his blimp, his crystal is missing.
Other mistake: When the clock is first shown in "Dances," the time is 7:40, but the title card reads: "1 hour 40 minutes until 9:00."