I filed a Radar bug on this several weeks ago, and unfortunately it still exists in the 9.0 GM. My app uses Core Motion, and whenever the Compass Calibration dialog appears it causes the app to go bonkers. The dialog will randomly flash and disappear. Each time it does this I get an -applicationWillResignActive, and -applicationDidBecomeActive call. It's like the calibration dialog is a separate app that randomly switches with my own app.
Occasionally, the calibration screen will appear and stay. It seems to work, and I can do the calibration, but once I get all the ticks ticked it freezes up. If I hit the Home button to exit out, it actually causes the calibration screen to disappear, and then control returns to my app. So, it definitely appears that the Compass Calibration screen is a separate app, and iOS 9 is getting very confused.
Anyone else seeing this?
-Brian