NBC (ended 1994)
|I think it was something to due with the budget and they decided to have Jessie in the film instead of ALex because Jessie was more associated with the Zach/ Kelly love story.|
|She was the replacement for Kelly and Jessie during parts of season 4/5.|
|In reality it might have been that he actor or the director didn't want to be in the movie. For fiction reasons she might have had a falling out.|
I agree in that the actress that played Leslie probably either had other priorities or didnt want to be associated with the show. I think it was around a year in-between the filming of the last College Years episode and The Wedding in Las Vegas. It was kind of weird that she was the only one not there though.