The Do Not Disturb scheduling feature that was released as part of the iOS 6 has been causing a lot of difficulties for many iOS 6 users. A lot of users have been noticing that the Do Not Disturb function was not automatically disabling itself as per the scheduling instructions. Apple has been very quick to react to this and they have issued a support article on their official website.
The support article number TS4510 refers to an issue with the Do Not Disturb mode remaining active even after the scheduled time had elapsed. A number of users reported that this issue occured immediately at the turn of the New Year whereas some users haven't had any problems until today. Whilst it may not be an immediate resolution, Apple iOS engineers have confirmed that the bug will correct itself and will be back to normal from the 7th of January.
In the meantime, users won't be able to rely on the Do Not Disturb feeature through the Setting App and manually turn the feature on or off until the issue rights itself next week. Go to Settings > Notifications > Do Not Disturb and make sure that Scheduling is set to Off. This should alleviate the issue for now.
Users have reacted really well to the inclusion of this feature in iOS 6 which allows them to accept who they want to receive notifications from through a set of rules that are defined through the Settings App. Everyone should be working perfectly find from the 7th of January but this does mean that Apple will have some serious work to do to ensure that this doesn't happen with iOS again when a New Year comes around.