The GA Democratic machine stayed with Truman.
But why? The Democratic party machines did not stay with Truman in other Deep Southern states, evidently. So why did Georgia stay loyal?
It's already been said: Richard Russell supported Truman.
^^^^
This.
A number of Southern Democrats (especially Georgia and Texas Democrats) ultimately showed more loyalty to the national party than to the Dixiecratic cause. Kind of similar to what happened in 1928 when Mississippi Governor Theodore Bilbo (a proud racist and strong supporter of segregation), despite the overwhelmingly anti-Catholicism of Mississippi, campaigned for Al Smith in Mississippi by spreading rumors that Hoover danced with black women. The result? A massive landslide in Mississippi while next door Alabama nearly went Republican.