Some of those republicans could also be disaffected Nikki Haley voters.  She got 77,000 votes in the Georgia primary against Trump despite dropping out 6 days before the primary.  

I think big turnouts are a sign that the pollsters got it wrong again and this is going to be a big win for Harris and down ballot democrats.  I just looked at the polls for Georgia and they have Trump up by 1 percent in the aggregate.