Are you sure the app was removed? Or did the icon just get removed from the home page(s)? Try swiping up on the home page to see the list of all installed apps to see if it is still there. Or look in Android Settings > App to see if it is still listed.
Norton cannot track what apps might get uninstalled.
To protect your apps from getting removed, you could try the Norton App Lock app. https://play.google.com/store/apps/details?id=com.symantec.applock Install that app and lock the Android Settings. That will help prevent any app from being removed.