Last week, the Arapahoe County Clerk and Recorder’s office discovered that 985 military and overseas voters had not been sent ballots by the Jan. 18 deadline.

“Because of a file naming mistake by one of our staff, our print/mail vendor was given the email voter list” instead of the list of voters who had requested a mail ballot, the office wrote. The federal Uniformed and Overseas Citizens Absentee Voting Act requires that people stationed overseas who request absentee ballots have them mailed 45 days before an election.

The clerk’s office discovered the error on Jan. 29, after individuals questioned why they received both mailed and emailed ballots. It contacted the Colorado Secretary of State’s office and sent the entire batch of delinquent mail ballots by Jan. 30 for the presidential primary on March 3.

“To ensure this does not happen again, we are adding back-up personnel as an additional check on file contents and transfers, and we’re also adjusting our internal notification and communication protocols,” the office wrote.

This is the second ballot-related mixup to affect Arapahoe County voters in the past six months. In the November 2019 general election, more than 660 ballots did not arrive in Aurora voters’ mailboxes until Election Day. The U.S. Postal Service had lost the tags on the ballots that would have allowed for a quicker delivery.