Time:

For three weeks in August, as election officials across the country were preparing to send out mail-in ballots to tens of millions of voters, the U.S. Postal Service stopped fully updating a national change of address system that most states use to keep their voter rolls current, according to multiple officials who use the system. A USPS spokesperson acknowledged the failure in response to questions from TIME, and said that at least 1.8 million new changes of address had not been registered in the database.

It is not clear to what extent the failure, which has not been previously reported, could compromise Americans’ ability to vote in this fall’s election. In normal times, hundreds of thousands of people move every week, and those numbers have increased during the COVID pandemic, which has forced millions of people, particularly young adults, to relocate at higher rates than usual, according to public polling and news reports. As of early June, some 3% of adults had moved and 6% had someone move in with them because of the pandemic, according to a Pew survey. That, and concern about the health risks of voting in person, experts from both parties say, will mean an unprecedented reliance on mail-in voting this year.