The Colorado Sun reports it is unclear how many of those voters opted to cast their votes in person or filled out their ballots in time and turn them in. It is also unclear how the issue might have influenced the Aurora mayoral race, in which the top two candidates are separated by fewer than 250 votes.
Griswold has called for legislative or regulatory changes to the system after Friday’s discovery.
The ballots were delivered to the U.S. Postal Service on Nov. 1 but didn’t get to voters until days later. Voters can request a replacement ballot if they lose or damage the original.