I did all 5 levels on legendary and even earned the achievement but did not get the challenge. Did anyone else have this problem?
I would doubt no one else is having this problem.
I had this problem as well and I also got the challenge for finishing the final level on legendary but it still didn’t pop
I also completed all on legendary. I didn’t complete the challenge either.
There are a ton of topics on the forums already about this. Play through the missions again on Legendary. It unlocked for me and friends after beating Episode 1 the second time. Easy fix.