You cannot keep a good bug down. This is what Bungie has learned as the disappearing Glimmer bug from last week emerged once again to force Destiny 2’s servers offline for about eight hours. While the issue wasn’t as widespread this week, enough players were affected that Bungie once again had to kill the servers and rollback player’s account information to the state it was in before the weekly reset.

In a blog post on Bungie.net, the development team has gone into some detail about the cause of the bug, and it is certainly interesting reading for anyone interested in just how intricate game development can be. The issue stems from a fix that Bungie put in place some months back to fix a bug with quest log sorting. Quests, which are treated like other inventory items, are timestamped when you receive them. The quest order was being broken when players finished a part of a quest, as the ordering system would issue a new timestamp at the time, overriding the original timestamp, and breaking the order of the quests.

While this should have been a perfect fix for the issue at hand, it had a knock-on effect on the rest of the clean-up process that occurs every time a player logs on. When you log onto the game, a process runs that ensures everything in your Inventory is matching up with what is live in the game, and the expected maximum counts for stacks of items. According to Bungie, ” The net result was that the game calculated the wrong cap quantity for stacked items (such as currencies and materials), which caused items above the cap to be lost.”

The reason that the issue returned this week is due to a crash. Some of the WorldServers were restarted after the 2.7.1.1 update. Because the servers crashed, the fix for the disappearing materials issue was never applied. Upon manual restart of the servers, players who loaded in on them were once again affected.

In their blog posts, Bungie highlights several learnings and new practices from this, to ensure something similar cannot happen again. Further safeguards are in place to ensure servers cannot start with an unexpected version of a patch, and the WorldServer crash issue has also been fixed and will be deployed at the start of Season 10. They also plan to streamline to rollback and recovery systems, so even if a character rollback is required in the future, it won’t take quite so long.