Camera background color don't update when changing it from code

Hello, i have a High-Definition RP project and i'd like to change the camera background color via script. If i change it in the editor it's just fine, but not from code. Background Type is set to color.

If i set the color like this, and then logging it console, it prints that the color is set, but in the game window and in the inspector nothing changes.

     public Camera cam;
     private void LateUpdate()
     {
        cam.backgroundColor = Color.black;
        Debug.Log(cam.backgroundColor);

      //taking a screenshot...
     }

Any help is appreciated. Note: its working in "3D" and "3D with extras" projects. Using unity version 2019.1.1f1, did not tried in other versions.