Crash when reactivating the app after switching to another

[jmgeffroy]

I/SurfaceView(11847): onWindowVisibilityChanged(8) false io.flutter.embedding.android.FlutterSurfaceView{b0628ab V.E...... ........ 0,0-1080,2154} of ViewRootImpl@ae32fc1[MainActivity]
I/SurfaceView(11847): surfaceDestroyed callback.size 1 #2 io.flutter.embedding.android.FlutterSurfaceView{b0628ab V.E...... ........ 0,0-1080,2154}
D/AndroidRuntime(11847): Shutting down VM
E/AndroidRuntime(11847): FATAL EXCEPTION: main
E/AndroidRuntime(11847): Process: com.mantano.iridium.IridiumApp, PID: 11847
E/AndroidRuntime(11847): java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.dispatchWindowVisibilityChanged(int)' on a null object reference
E