I have been working on completing the achievement lists for all the 360 Halo games before they go offline and one of the last online ones I have is Halo 4’s “The Challenger”. My service record says I’ve completed 25 challenges, so why has the achievement not popped? Please help!
For anyone else struggling, keep going! I was able to pop the achievement when I completed 27 challenges! I hope anyone else who is having difficulty with this stubborn achievement pops it soon.