Bug External display shows black screen after disconnection until the app and/or scene is restarted

We have an iPad connected to an external display. When the app starts everything works fine. However, when we disconnect the iPad from the display, then connect it again - the external display shows a black screen until the app is restarted (or the scene is reloaded).

We can reproduce the same behavior without disconnecting the external display. We simply have to turn the display off, put the iPad to sleep, then wake them both back up - black screen until the app is restarted or the scene is reloaded.

After closing the app (and before restarting it) the external display does show the iPad's home screen. So the issue is with Unity (not faulty hardware).

Our code is based on the official documentation:
https://docs.unity3d.com/Manual/MultiDisplay.html
https://docs.unity3d.com/ScriptReference/Display.html

Reproduced:
Unity 2019.4.3f1 LTS
Unity 2020.4.0f1 LTS

Bug report:
Case 1253206

This is a critical bug for us.

Please help!