In case anybody else runs into this problem: Apple got back to me on the Feedback Assistant report. I wasn't explicitly linking Intents.framework to the target and it was causing this problem. I'm not sure why it worked in older environments, or why it still worked when the debugger was attached, but clearly linking Intents.framework is the proper thing to do anyway.

I started trying to implement this today and found the same problem. One thing to note is that on beta 3 I see differences between behavior on an iPod Touch (no multiple window support), and iPad or the simulator. The App and Scene versions just never fire under any conditions I can find. I don't see the initial launch of an app on an iPad or on any simulator, but I will see subsequent background/foreground events. (On the iPad when I create a second scene I do receive a .active phase change.) On an actual iPod Touch (7th generation) device I see the View .active case on every launch.