https://www.gamespot.com/articles/destiny-2-leviathan-raid-shuffles-things-around-af/1100-6453435/

Each weekly reset in Destiny 2 presents you with a slate of new things to do for the week, including another batch of rewards in the Leviathan Raid. In a move that should help to keep it feeling fresh from week to week, the reset also apparently shifts aspects of the Raid around.