It's hard to judge without seeing the root cause analysis, I would say it'll be pretty much impossible to replicate production, given the amount of users and also i'm guessing it's tide in with the likes of xbox/playstation, so it would have depended on how good xbox and playsation envs are. So it may not have been possible to replicate the issue in uat. May also just have been human error, someone rolled out a wrong version of the db changes, and it was a data change db change, and those f**kers are impossible to rollback, so you try to fix forward, and if that fails you tuck your tail between your legs and pull the backups out.