In a container view, a navigation controller's

I have created an application which needs to have a bar above the navigation bar and other views. To accomplish this, I am using a view controller with a view for the top bar, and then a container view for everything else. Sometimes, the top bar needs to be hidden. I'm using autolayout to hide the top bar (set its height to 0), and the container view expands to fill the screen (container top equal to the top bar bottom). The container view contains a navigation controller because I need a navigation bar below the top bar sometimes. When I start the app, this all works fine as shown below:

As you can see, the navigation bar stays the desired height, which is expanded to include the status bar

However, when the top bar is tapped, I use a segue to present (not push) a view controller from my root view controller (not the container), and then I look at the same screen with the navigation bar, the navigation bar is no longer extended and it overlaps the status bar as seen below:

Why would presenting a view controller break this? And then how could I rectify this or prevent it?

One possible solution I could do is present a view controller from within the container view, that works, I would just have to set the current view controller in the container to a delegate of the root controller, so that when the top bar is tapped, it tells the view controller in the container to present the new view controller. This would not be my first option however, especially if there are other scenarios which cause this problem.

Thanks for any help!

You need to turn automaticallyAdjustsScrollViewInsets off for all of your child view controllers and manage the insets (or setup so they aren't required) yourself. By default automaticallyAdjustsScrollViewInsets is on for all view controllers (which is what you want for 'full screen' presented VCs.

At the moment you see controllers almost randomly updating to reorganise themselves for the scroll insets as the VC hierarchy changes.

I'd probably turn automaticallyAdjustsScrollViewInsets off for all VCs (apart from root) and change your header view so that it's full height or status bar height (which should be the length of the topLayoutGuide of the root VC). When collapsed to status bar height your header view could also change colour to match that of the current top VC.