In Fulton County, even if one moves to a different address and haven't updated it, they can still vote from their old precinct and their vote is valid
A claim made by a Twitter account with the handle @Peoples_Pundit states that "in Georgia, there are 132k CoA flags in Fulton County, alone." CoA stands of 'Change of Address' and the user claims that because of this, 132,000 ballots will likely be ineligible in Georgia. @Peoples_Pundit is Rich Barris, the owner and operator of Big Data Polling. The claim was subsequently picked up by many conservative right-wing organizations, including Gateway Pundit.
According to the Fulton County website, "Voters are required to notify the board of registrars of their county of residence whenever they move. If they move within the same county in which they are registered to vote and don't notify the registrar at least 30 days prior to an election, they may vote in your old polling place for that election. However, they must file a notice of their new address as soon as possible. Similarly, if someone moves outside the county in which they are registered to vote within 30 days of an election, they may vote in your old precinct for that election." This basically means that a person is eligible to vote at their old precinct even if they have moved inside and outside their county and have not updated or registered their new address. They will not be allowed to vote in their new precinct, but can still cast their vote from the old one.
The claim implies that if one moves and votes from their old precinct, their vote will be disqualified because of change of address, however that is not the case in Fulton county. What matters is that a person votes from the right polling booth, and if one tries to vote from the wrong precinct, they will not be allowed to vote.
The population of Fulton county is just over a million. According to the Pew Research Center, around 22 percent of U.S. adults moved due to COVID-19 or know someone who did. This means that many people could have moved in and around Georgia, and their voting booths might not have matched their current address if they did not update their details. However, that does not invalidate their votes.