Of course, I figure it out shortly after posting the question. The issue was NSUbiquitousContainers entry in info.plist was wrong when I first ran the app. I fixed it and re-ran. But, the entry is only reloaded by iOS when the build number changes. Bumping that and now it's working fine.

I'm attempting my own Live Listen iOS implementation too. Can anyone shed light on how to accomplish it? I know it can be done as Chatable, Fennex, and a few others have it. Thanks in advance.