For three weeks in August, the U.S. Postal Service stopped updating the national change of address system most states use to keep voter rolls current, according to multiple officials familiar with the system.
A USPS spokesperson said that at least 1.8 million new changes of addresses had not been registered in the database. It is not clear to what extent the USPS's failure to update the system could affect Americans' ability to vote in the upcoming election.
Although hundreds of thousands of people generally move every week, the pandemic has forced people to relocate at higher rates than usual. A Pew survey showed that, as of early June, around 3% of adults had moved and 6% had someone move in with them as a result of the pandemic.
Several companies licensed to use the system alerted officials that they were seeing a drop-off in the number of change in address for August by as much as 95%.
"It's a significant screw-up," said one vendor, who spoke to TIME on the condition of anonymity.
TIME reports that several of the states it contacted about the issue were unaware it existed, while others had already sent ballot applications based on faulty databases or had to delay sending out their ballots to fix incorrect addresses.
The USPS said it fixed the issue and restored missing data on September 14.