In a new support document, Apple acknowledged the problem, describing it as "after January 1st, 2013, 'Do Not Disturb' mode stays on past its scheduled end time," the Telegraph reports.
It said, however, that "Do Not Disturb scheduling feature will resume normal functionality after January 7, 2013. Before this date, you should manually turn the Do Not Disturb feature on or off."
Apple iOS developer Patrick McCarron suggested on Twitter that Apple had made a common mistake by incorrectly formatting how the iOS software defines dates, allowing the underlying software, based on Unix, to define the final week of 2012 as ending on January 7.
According to the report, that would mean the feature would resolve itself as Apple suggests.