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".
Continuity mistake: When the gang watches an advanced copy of "The Wood", and Jade watches the fake phone call between Beck and Tori, the background and scene changes from Beck at School, in the day, to Tori at Home, at night (viewable through windows) This isn't noticed by Jade. (00:13:30)
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.