When my app is running on simulator and I press the home button it enters the background properly. But when I put the app back in the foreground, it has apparently dropped all the managed objects in memory, and the app crashes when I try to resume using it. There's no code in the any of the callbacks for the app changing state that would cause that, and the app has never displayed this behavior before.
What changed was going to xCode 6 / iOS 8 on the simulator, and I also applied "Reset content and settings" in response to this problem.
The app behaves problem-free on actual devices, both iOS 7 and iOS 8. Is this another bug with the new iOS simulator?