title: Why does my iOS build behave differently after closing and restarting the app
body: <p>We have a hybrid app that is a mix of Objective C and Swift that is showing some strange behavior in classes that haven't been touched in a long time.  If we do a fresh build from Xcode the app works fine, but if we close the app and restart it, it behaves totally different.  We re-attach the debugger and have seen viewWillAppear called but viewDidAppear is not called after re-opening.  Other things like NotificationCenter Observers don't fire after closing and re-opening either.  We've tried to track this down and I wish there was code that I could share that would point in the right direction, but it's a general thing in the app that is happening across most classes.  When building for test flight it behaves the way that misses the viewDidAppeaer and the observers.</p>