[iOS] Subview stuck on top of view stack after code-push update/install

Description

Hi, thanks for the great project. Fully appreciate this is probably an issue with our codebase, but figured I'd start here.

For the iOS app we're developing, we need to add screen obfuscation when the app is backgrounded because it contains sensitive information. We are using applicationWillResignActive and applicationDidBecomeActive to show/hide a blurred subview. The screen obfuscation works great until the app receives and installs a code-push update. The update is installed ON_NEXT_RESUME, so when the app is backgrounded and foregrounded, for some reason the update is installed but the BlurView is not removed (stuck on top of the view stack). The workaround for us is to swipe the app close and open it again. Any hints on what we might be doing wrong? Should we be detecting the code-push update install and forcibly removing the BlurView?

Reproduction

Implement UIBlurEffect to obfuscate screen via applicationWillResignActive and applicationDidBecomeActive in AppDelegate

react-native app should be configured with:

const codePushOptions = { 
checkFrequency: codePush.CheckFrequency.ON_APP_RESUME,
installMode: codePush.InstallMode.ON_NEXT_RESUME,
};

Install app from store
Push code-push update
App receives update and is prepared to install it ON_NEXT_RESUME
Background app
Bring app to foreground
Subview BlurView remains atop the view stack and obfuscates the screen

Additional Information

react-native-code-push version: v2.1.0-beta
react-native version: v0.43.1
iOS/Android/Windows version: iOS 10.3
Does this reproduce on a debug build or release build? yes
Does this reproduce on a simulator, or only on a physical device? both

Sample AppDelegate.m

- (void)applicationWillResignActive:(UIApplication *)application {
    self.window.backgroundColor = [UIColor clearColor];

    UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleExtraLight];
    UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
    blurEffectView.frame = self.window.bounds;
    blurEffectView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

    blurEffectView.tag = 1234;
    blurEffectView.alpha = 0;
    [self.window addSubview:blurEffectView];
    [self.window bringSubviewToFront:blurEffectView];

    // fade in the view
    [UIView animateWithDuration:0.5 animations:^{
        blurEffectView.alpha = 1;
    }];
}

- (void)applicationDidBecomeActive:(UIApplication *)application {
    // NSLog(@"Hiding blur");
    // grab a reference to our custom blur view
    UIView *blurEffectView = [self.window viewWithTag:1234];

    // fade away colour view from main view
    [UIView animateWithDuration:0.5 animations:^{
        blurEffectView.alpha = 0;
    } completion:^(BOOL finished) {
        // remove when finished fading
        [blurEffectView removeFromSuperview];
    }];
}

microsoft / react-native-code-push