The Division's servers will be going down for maintenance again tomorrow at 5 AM EDT / 2 AM PDT for about two hours.
The only known bug being fixed, according to the current changelog, is an issue where players were getting rewarded for killing a High Value Target boss even if they failed. No word on if this was considered an exploit that could get you permabanned.
More could be added before the end of the maintenance, because apparently there are still a few things wrong in the game. Ubisoft released a rather large list of known bugs in the game, some having been introduced with the recent 1.2 Conflict update that was released earlier this week.