QAbstractLight's methods no longer work in PySide6

In PySide2 QAbstractLight's methods: setIntensity() and setColor() were working correctly, but for some reason, in PySide6 these methods are not changing underlying shader. No error messages are shown when these methods are used and these attributes are actually retrievable with intensity() and color() methods but these changes have no impact on the rendered result. For some reason these attributes are not passed to the shader. 

Minimal working example . If You try this example and change color from "white" to "red" it will work, but if You change imports from PySide2 to PySide6 and leave all the code intact color will still remain "white". Method setColor("red") is ignored. Same with intensity. It is also ignored