https://www.polygon.com/2018/9/10/17842020/destiny-2-forsaken-players-last-wish-raid-glitch-loot

The Last Wish raid in Destiny 2: Forsaken begins this Friday. However, over the weekend, players found a way into the raid’s entrance and stumbled upon a hidden chest. Inside, players were able to claim early drops from the unreleased raid, as well as poke around a bit more.

The glitch involves going under the world in Forsaken’s Dreaming City location. Players then have to do some serious jumping and hit certain loading walls just right, otherwise they’ll be killed or become stuck, needing to start over again. But players who’ve managed to push their way through have essentially confused the game, making it believe that the players have loaded into the Last Wish raid.