Depends on the state. Looks like Carter is registered in Georgia. According to an article from 2020 when Republicans were bald face lying that long dead people were voting a lot, someone from the Georgia Secretary of State’s office is quoted as saying secrecy rules don’t allow rejecting a ballot when a voter dies before Election Day.
“You can’t go back and get that ballot back out. It’s just physically impossible, given the privacy rules in our state,”. May or may not still be accurate, or may have never been accurate, but that’s what the first article I found when searching says.
The other big chunk is people who have the same or a similar name. Like “It says here David Jones died five years ago, but David Jones voted today. Suspicious?” “Dude, I’m David Jones Jr. The David Jones who died was my dad, David Jones Sr. Dick.” Or whatever.