iOS11, Xcode 9, iPhone6 Plus, UIDeviceDidChangeOrientation notification not called,UIDevice.current.orientation only returns portrait

Question

Im using xcode 9, ios 11. I have an observer for UIDeviceOrientationDidChange and it works well on my 6s, but on the 6s Plus, it is not called when the device changes orientation, and checking UIDevice.current.orientation shows portrait at all times regardless of device position.

Anyone have any information about this?

Code is really basic

   NotificationCenter.default.addObserver(self, selector: #selector(showHideRotateOverlay), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil)

added in viewWillAppear. Works in ios 8, 9, 10.

Portrait and LandscapeRight are enabled in settings. this DOES WORK on previous ios versions