Totally Awesome: The Greatest Cartoons of the Eighties Book Review
“It was always my understanding that Bill made a casual remark to someone about Lorenzo not sounding like him, and that person got word back to the show’s producers, who mistakenly took it to mean that he was unhappy with Peter’s voice.”
Actually I read the recollection by Michael Gross. It was Murray who made the observation to Reitman and then he informed the RGB production team to change the voice actor.