When the lottery bug occured and displayed 0 as the winning number, all participants (including the actual winner), were told that they lost and had the option to withdraw their deposits. When the bug was fixed and the lottery servers' results were finally synced with the housing wards, some of the actual winners had already withdrawn their deposits - which of course, is a condition that normally can't occur. The conclusion of the first round of lottery had already been delayed over a month, and it just didn't make sense to delay it some more to ensure that gil was collected from every winner who had previously withdrawn their deposit. Instead they're implementing this NPC that allows those winners the option of returning their deposit in exchange for those posters.