Act Adversaries II, challenge

3.25 Challenge
Act Adversaries II

Is there a bug on this one, challenge Act 7: Arakaali, Spinner of Shadows. I've taken this boss, you have to do it to get to act 8. I've done it twice now after I finished act 10, but the challenge is not carried out.
Does anyone else have the same error ?

Yep, after check, Arakaali doesn't work for me too