Open Radar

 
Link to videos and Example Xcode Project:
https://drive.google.com/open?id=0B4Mo8cg2oLGKeHZLYmw3V2VsVUk

Summary:
On iOS 10 beta a custom transition with a container view that wraps and positions the toViewController. The UILayoutContainerView gets resized after finishing with "completeTransition". In iOS 9.3 or lower the sizing of the previous toViewController is not changed.

Steps to Reproduce:
Run the attached example app with iOS 10.0 on  Xcode 8 beta 6:
1- Tap the "Go to Second Level" button to perform a modal presentation with the custom transition.
2- The Label attached to the bottom of the View Controller is visible.
3- Tap the "Go to Third Level" button to perform another modal presentation with the custom transition.
4 - Tap the "Go to "Back to Second Level" to dismiss the View Controller. 
5 - The Label attached to the bottom of the View Controller is no longer visible.

Run the attached example app with iOS 9.3 or lower on  Xcode 8 beta 6:
1- Repeat the above steps
2 - The Label attached to the bottom of the View Controller is still visible after dismissing the View Controller.



Expected Results:
The Label attached to the bottom of the SecondLevelViewController should always be visible. This happens on iOS 9.3 or below.

Actual Results:
The Label attached to the bottom of the SecondLevelViewController disappears after dismissing the ThirdLevelViewController in iOS 10 beta.

Version:
iOS 10.0 (14A5339a)

Notes:
- Attached you can find videos of the behavior in iOS 9 and iOS 10 as well as an Xcode Example Project.
- Not sure if this is an iOS 10.0 beta bug or simply a breaking change but it broke some functionality in one of our apps.

Configuration:
iPhone 6 iOS 10.0 beta