Based on Apple sample code.
Requesting a scene session refresh in certain states can cause scene windows to go blank/black.
Build and run the attached sample code. See the code and detailed comment in SceneDelegate.sceneWillResignActive(_:).
Once the application is running, transition slowly into the application picker, and then wait.
Two seconds after you initiate the transition, the application request a scene refresh to simulate sync data coming in off the network that requires a UI state update.
On an iPad, this bug can also happen if a scene session refresh is made while in 2-up mode, and moving the splitter.
The UI state updates. (In this sample app, there should be no visual change.)
The application window goes blank/black and becomes unusable.
iOS 13.1 b2
This problem happens on all device/hardware classes.