Bungie Explains Destiny 2's Recent 20-Hour Outage

Zack Zwiezen writing for Kotaku

Bungie realized that this was being caused after it moved some “currently incompletable” challenges into a different area of the game’s data. To do this, Bungie used a “very powerful” tool that lets the studio tinker with a player’s game state and account. Apparently, due to a configuration error, Bungie accidentally “re-ran an older state migration process” used in a past update. Because of this error, the tool copied old data from this past update into the current version of the game, which basically undid some players’ recent in-game accomplishments