State Department officials handed over Hillary Clinton's schedules from the days surrounding the 2012 Benghazi, Libya, attack, revealing a mistake on the documents that might have helped to keep them hidden until this week.

The schedules show Clinton spent the week before the attack traveling through southeast Asia and Russia as conditions in Libya deteriorated.

Clinton's schedules from Sept. 1, 2012, through Sept. 9, 2012, are misdated, however. Although they accurately reproduce her activities from those days in 2012, the schedules are dated as though they pertained to 2010.

State Department officials told Citizens United that the agency does not correct inaccurate records during the FOIA process and only produces the files as they appear in government archives.

The mistake, officials told the conservative group, occurred back in 2012, when someone on Clinton's staff must have entered the date incorrectly into Clinton's schedules.

But the error could have shielded Clinton's schedules for the week leading up to Benghazi from disclosure for years. Anyone who requested calendars specifically from those dates may have been told no such records existed because a typical search would not have turned up any documents whose dates matched a request for schedules from the week immediately preceding the 2012 Benghazi attack.

Citizens United and the Associated Press, which are on the same production schedule, only received planning material from those nine days because they asked for all Clinton's calendars.

"Accuracy matters," J.T. Mastranadi, political director for Citizens United, told the Washington Examiner. "The State Department should explain this error to the American people in detail and correct the record immediately."