I remember when the trailer dropped a few people heard rumours that a lot of its crew were people Harmon had scared off Rick and Morty or driven away due to his attitude.
Given that Dan didn't even know Justin was pitching other shows, it suggests that this is Justin beginning to sever his ties with Harmon.
Yeah I remember that drama and I think Dan himself was the one who leaked it. After awhile I assume you'd want to drop all the pretentious meta bullshit and just tell a show about weird aliens. Less 30 Rock and more 3rd Rock From the Sun.