Open Radar

 
I have an app with a Tab Bar Controller with two tabs. In each tab is a Navigation Controller with a root view controller. One of the root view controllers has a UISearchController and adds the search controller's search bar to its view. If I navigate away from the tab with the search bar whilst the search controller is active then the tab's contents is missing when I navigate back.

Steps to Reproduce:
1. Open the included project in Xcode.
2. Run the app.
3. Navigate to the 2nd tab.
4. Tap on the search field.
5. Type the letter 'a'
6. Tap the 'Search' key on the keyboard to dismiss the keyboard
7. Navigate to the 1st tab
8. Note that the SearchViewController's 'viewWillDisappear' and 'viewDidDisappear' aren't called
9. Navigate back to the 2nd tab
10. Note that the view is missing and there is a black rectangle instead.

Expected Result:
I'd expect that the SearchViewController's  'viewWillDisappear' and 'viewDidDisappear' were called.
I'd expect to see the 2nd tab's view when I navigate back to it.

Actual Result:
The SearchViewController's  'viewWillDisappear' and 'viewDidDisappear' aren't called.
The view is missing when I navigate back to the 2nd tab.