Has Louisiana gone main stream? Until fairly recently what you described for Georgia held true for Louisiana.
.Louisisana is same as usual
In Louisiana there is a second round (runoff) between the top two candidates if no candidate wins a simple majority (more than half of the votes) in the first round of balloting. That happens more often with open seats, as incumbents more easily win majorities. The runoff constitutes the general election under Louisiana law even if the general election had two candidates of the same party, a phenomenon which frequently occurs. Historically, the Democratic Party was dominant from the late 19th through much of the 20th centuries, especially after the state legislature disenfranchised most blacks at the turn of the 20th century, weakening the Republican Party.
https://en.wikipedia.org/wiki/Nonpartisan_blanket_primary