Denoiser kills alpha during render

Hi,

I’m scratching my head over this.
Here is the same scene, same settings.

One screenshot is taken practically after the light cache has calculated.
The screenshot on the right is the render after it’s completed the denoiser

As you can see, the alpha has vanished.

Is there a setting I’m overlooking perhaps?
Removing the denoiser, the alpha stays intact after the render.


…and I’ve posted into 3DS max instead of Maya. Sorry!