So this is a story related achievement that should pop as the 13th (3rd last) achievement in the game, I say should since quite a few have experienced problems getting this & even other achievements to pop ...
Anywhooo, close to the ending of the game you'll get a code from an interrogation that you have to use on an elevator door, once you do that & enter the door the achievement should pop but odds are it won't, now I tried to continue a tiny bit further to see if popping the next achievement (which are relatively close) would solve the problem but it didn't so dashboard & quit/restart the game (I actually noticed during the small bit I had to re-do that autosaves now we're working which apparently they hadn't before where I kept respawning in the ruin/castle next to the scientist "Shelly" so this might be an early indication that something is wrong & a restart might actually be possible as early as this point,IDK?) Anywhooo after the dashboard restart followed by a "continue" from my last working autosaves all the last 3 achievements popped without any problems
Now as for avoiding problems with other achievements I'm 99% sure that this is one of the ID@Xbox games that seem to get achievement problems if you resume the game again without having really quit it, it certainly did the trick for me so simply make sure that if you ever
need to stop playing in any way then make sure to QUIT THE GAME fully
, this can be done from in the game or from the dashboard by pressing the
button & scroll down to "The Long Reach" then while having the game highlighted press
to open Game Options & scroll to the very bottom & click "QUIT"
Hope it helps, Good Luck 🍀