I noticed a bug using the last version v4.2.0-alpha.23
Here is a playground showing it: https://www.babylonjs-playground.com/#09U2VZ#1
You have to use the default rendering pipeline with HDR textures set to true and use the function addCamera.
You will get the error in the console:
Uncaught TypeError: Cannot read property ‘isSupported’ of undefined
Hope that helps!