Someone on reddit who lives in GA HD-176 (he's a Democrat, for the record) had this to say about the race that would explain a lot:
"From my point of view this was always a two man race between Patten and Burchett with the majority of people not even knowing that the two Democrats ran. Patten is a Democrat turned moderate Republican (if there's even such a thing anymore) and Burchett is a Trump cultist. The race was framed as the Republican Burchett vs the Democrat Patten so I suspect an inconveniently large number of Democratic votes went to Patten"
Finally - good explanation of results.
Or just dem excuses for another sh!t performance.
Neither of the Democratic candidates had money to turn out voters and the local Democratic county committees are decimated (if they even exist).