From what I understand this is a hand-recount, it does not check signatures for example so we do not want to confuse viewers by calling it an audit as it is not a full check like an audit would be.
The overlooked ballots all came from one county and were missed on Election night.
The 2,600 ballots in Floyd County were cast mostly in favor of the president. More than 1,600 were for President Trump, over 800 were for Joe Biden.
Election Official, Office of the Georgia Secretary of State
“The situation in Floyd County, where they found 2,600 ballots that they did not upload on election night. Um, again, this is why you do the audits. There’s [sic] no issues with any of the equipment or anything. They just didn’t scan these ballots it looks like.”
From NTD News