The ballots are early voting ballots (usually called absentee ballots) that can either be mailed in early or dropped off at a polling place on election day. The ballots that they’re still counting are the ones dropped off on election day. They’re all legitimate ballots IF they were turned in by a voter who signed the ballot and there’s a legitimate time-stamp on the ballot by a poll worker.
Results in this election vary widely by county and by city within the big counties (Maricopa and Pima), so if there are still numerous ballots to be counted in cities that McSally won big, then the vote total could swing back the other way.
Maricopa County looks fishy to me. In the first 950,000 ballots cast that were counted by early Wednesday morning, Sinema only had a 8000 vote lead, but Sinema somehow trounced McSally by about 20,000 votes in the last 150,000 ballots counted since Wednesday morning. That seems highly unlikely to me. The only legitimate explanation for such a sudden change in Sinema’s percentage of the votes would be something like a large number of dropped-off ballots being counted from the college neighborhoods near Arizona State University.
I would think this election can be audited in a recount, where McSally’s team could check for valid signatures on the dropped-off ballots. It’s very surprising to me what happened today in the Maricopa County totals.
If in fact there are around 600,000 total early ballots to be counted after election day, then there should be roughly 250,000 more ballots to the counted in Maricopa County alone. So this could easily swing back the other way in McSally’s favor, but today was an odd day.