Steps to reproduce:

Note: make sure 'Multitasking Gestures' are enabled on the device in Settings > General.

1) Open any existing project or create a new one.
2) Build the project for iOS.
3) Deploy the project ta a device via Xcode.
4) Open the app.
5) Using four fingers, slowly swipe to the sides. This should start switching between open apps.

- The area of the app becomes black when starting the gesture and comes back to normal after swiping a short distance. Only reproduces on iOS 9.

Devices reproduced on:
iPad Pro, iOS 9.2.1
iPad Mini, iOS 9.3.1

Did not reproduce on:
iPad Mini, iOS 7.0.2
iPad Air, iOS 8.1.1
iPad 2 8.1.2

RESOLUTION:

The problem is caused by a bug in iOS compositor that is impossible to work around. The bug is exposed during our attempt to render extra frame just before app goes to background: we use UIView snapshotViewAfterScreenUpdates API any use of which results in the black screen. Since calling that API is needed for the extra frame to be actually visible on screen and cached by iOS in the task switcher, we've added a checkbox in the user settings to allow users to select whether they need extra frame being rendered or not. The checkbox is enabled for upgraded projects and disabled for new ones.

At the moment the extra frame is still rendered even if the checkbox is disabled, but the render results are not guaranteed to be on screen or in the task switcher.