The Great Ping Pong Scam - S1-E11
Other mistake: In the episode 'The Great Ping Pong Scam,' Tori goes up to see Jade. Later on in the conversation, when Lane appears, Tori says something to Jade and you can tell that Tori is not looking at Jade.
Other mistake: In 1-7: 'Robarazzi', Robbie shows a video of Jade and Beck talking in a car. In the middle of the conversation, Jade states she had tuna fish for lunch, but in this episode, when Jade is listing things she hates, she lists "tuna fish".
Other mistake: When the gang is trying to find the letters to spell Ke$ha at Tori's house, Robbie decides to go give the extra ice cream to the kids at the park. When he comes back he says that there were kids there with their moms, despite the fact that it is late at night, as we can see out of the window.
Other mistake: Robbie gives Tori a chocolate leaf-blower as a present to cheer her up. Then when Robbie leaves to go join Cat at the Platinum Music Awards, he supposedly takes his chocolate leaf-blower present with him. But, in the shot where he leaves Tori's house, the bag that the chocolate leaf-blower was in is still on the floor.
Answer: The Director hated working with Melinda, but knew that her superstar popularity and status would get his movie a big buzz and higher ratings. And the movie was discontinued for a re-audition to fill-in Melinda's leading/major role.