The code which handles death in game was changed in the update in order to accommodate the coin pouch, but was done incorrectly and wasn't set up to handle stacks of other items, which caused certain items in a player's inventory to become a stack of 2,147,483,647 coins. 2,147,483,647 is the maximum value a 32-bit signed integer can take, which is what data type RuneScape uses for item quantity.
Jagex immediately took action by taking the Old School servers offline on 11:54 a.m. (UTC) after announcing to do so five minutes earlier, around 20 minutes after the update went live. Hours after the glitch occurred, Jagex announced they were performing restoration (a rollback) of the game.
After the rollback was finished and the servers were made online again, Jagex said they would be removing illegitimately acquired membership from accounts that was from purchasing bonds via money produced from the glitch. They also said those who abused it would be temporarily removed from the game.
- Jagex. Mod Ash's Twitter account. 12 July 2018. Mod Ash: "Someone was updating the death code to handle the new thieving pouches, and they kinda did it wrong."
- Jagex. Mod Ash's Twitter account. 12 July 2018. Mod Ash: "Looks to me like someone was trying to write a check to avoid overflowing max int, and they did it very wrong."
- Jagex. Mod Ash's Twitter account. 12 July 2018. Mod Ash: "The death handling of the new pouch item wasn't set up to handle stacks of any other item."
- Jagex. Old School RuneScape's Twitter account. 12 July 2018. Old School RuneScape: "We're turning Old School RuneScape off for a while whilst we investigate a potential issue. Apologies for any inconvenience, we'll return service as soon as we're able to!"
- Mod Sween. "Old School RuneScape Status Update." 12 July 2018. Old School RuneScape Forums.
- Jagex. (12-July) Old School RuneScape Offline. 12 July 2018. (Archived from the original on 12 July 2018.)*