I’m not sure if it’s because I own the pre-order bandana skull from Gamestop, but the achievement for this will not unlock for me. I do not have the skull active while attempting this.
You still have to find it yourself
I apologize if I wasn’t clear. The bandana skull achievement will not unlock, after picking it up. I offered that the problem might have been because of the preorder bonus being installed, but none of my achievements are currently unlocking so that’s not the issue.
The preorder Bandana skull is for Halo 2.
Anyhow, I’m having the same issue, though not with that achievement. I stopped unlocking achievements an hour and a half ago or so. I found a thread on the Xbox Support forums, I guess other people are experiencing this with other games as well.
http://forums.xbox.com/xbox_forums/xbox_support/xbox_one_support/f/4270/p/1865064/5038452.aspx