React Native App crashes on Launch Screen on device

I'm starting with React Native, everything works fine in the iOS simulator. I decide to try it on a device.

The app launches, I can play with it, I close/reopen it around 4 or 5 times, and then somewhat randomly the app crashes on Launch Screen (the one with "Powered By React Native"). It just shows the screen, and the app crashes to the iPhone home screen.

Any idea how I can further debug that?

Edit: I added Bugsnag in my AppDelegate.m, but bugsnag doesn't detect anything when the app crashes.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{  NSURL *jsCodeLocation;  [BugsnagReactNative start];  // Rest of code  }