Here's why:
* Melissa Joan Hart's real-life schedule: As the main character, Melissa had a busy schedule filming the show. It's possible her sister's own schedule made it difficult for her to appear in as many episodes.
* The writers' direction: The show started focusing more on Sabrina's personal growth and relationships with other characters, like Libby and Valerie. This shift naturally meant less screen time for other characters like Jenny.
It's important to note that Jenny wasn't completely absent from season 2. She still appeared in a few episodes, showcasing her friendship with Sabrina.
Although her role decreased, Jenny remained a beloved character for the show's fans.