(CNN) — The Palm Beach County Supervisor of Elections said Gov. Tim Walz, the Democratic nominee for vice president, was misspelled as “Tom” Walz in some ballots that were emailed to overseas voters last Friday. “The error was isolated to 257 electronic ballots,” the Florida county’s elections supervisor Wendy Sartory Link said in a statement to CNN. The office was made aware of the error less than 18 hours after the ballots were sent and the error was “immediately corrected.” Link said the vendor made a manual change to the approved ballot “without authorization” and incorrectly typed “Tom” instead of “Tim” Walz. The affected voters were emailed a recommendation to download the updated ballot. Link said the error would not affect the counting of the votes.