Not sure who has this achievement, I think JT & Dark might, you have to win a Public Annex match on each Combustible & Flashback Map and it's worth 75 points.
The Maps are of course
Canals
Gridlock
Mansion
Subway
Tyro Station
Flood
Gold Rush
Fuel Station
I'm missing two of the maps, Canals and either Flood or Subway, not quite sure, but i've just found this pic which shows the description for the achievement, which now says 'Won a Ranked or Social Annex match on each of the Flashback & Combustible Map Pack Maps' which says to me that it can now be boosted, so if true, who's up for boosting this achievement?