You'll need to play a full game on each map for this to unlock. You'll have a total of 12 maps to play on:
- City Hall
- Downed Bird
- Evac Zone
- Liberty Island
- Parking Deck
- Pier 17
Some maps are not available in certain gametypes like CTR, so you'll have to move onto a different one for it to pop up. You also don't have to play a full game for it to unlock, you just need to be in it when it ends. As long as the map loads and you're there, then it counts.
I got put into a game of Assault right at the end. I was on the respawn screen for 2:00 minutes and the game ended and the achievement unlocked! These cannot be gained by playing in a Private Match.