The tutorial has us put the updateLocations call in the MapViewController inside viewDidLoad when it should be in viewWillAppear. The error causes the app to crash if the user opens the app, goes to the map tab, then adds a location, then deletes a location, then returns to the map tab and moves around the map. I think it’s because the viewDidLoad only gets called when the tab is initially opened so if the user changes something and returns to the tab the updateLocations function isn’t called and there are phantom pins on the map.
It appears that this is still in v5.0 but I haven’t tested whether it is still a bug because I’m still running Xcode 6.4.
I see that this gets fixed later on.