NPE on resume activity

Vuforia SDK Version: 2.0.30 - Description with steps to reproduce: Unity project using Vuforia had activity paused in background. Clicked app icon on home screen to bring to front. Crashed immediately with following stack trace. Has only happened once so far. java.lang.NullPointerException at com.unity3d.player.e.c(Unknown Source) at com.unity3d.player.UnityPlayer.g(Unknown Source) at com.unity3d.player.UnityPlayer.windowFocusChanged(Unknown Source) at com.qualcomm.QCARUnityPlayer.QCARPlayerSharedActivity.onWindowFocusChanged(QCARPlayerSharedActivity.java:350) at com.qualcomm.QCARUnityPlayer.QCARPlayerNativeActivity.onWindowFocusChanged(QCARPlayerNativeActivity.java:77) at mobi.aroha.cariana.ui.AbstractMainMenuScreenActivity.onWindowFocusChanged(AbstractMainMenuScreenActivity.java:1184) at com.android.internal.policy.impl.PhoneWindow$DecorView.onWindowFocusChanged(PhoneWindow.java:2638) at android.view.View.dispatchWindowFocusChanged(View.java:7557) at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:938) at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3013) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4898) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773) at dalvik.system.NativeStart.main(Native Method) - Development OS (Mac OS X, Windows, Linux): Windows - Mobile OS and Version: 4.1.1 Android - Mobile Device Manufacturer and Model name: Samsung S3 - Do the Vuforia Sample Applications show the same behavior?: No