Matte object with refraction showing in alpha

[HeadOfficeStudio]

Hi, can someone explain why my matte object shows in the alpha and in the beauty pass? See screenshots.

I have scene with a vray volume grid and phoenix smoke, a skyscraper building (matte object, its parts are grouped, glass, walls etc) group is set to: matte object, alpha -1, matte for ref/refr)

The beauty pass still has ghosted marts of glass visible...and shows in the alpha....why? I have tried variations of checkboxes in the vray properies but to no avail.

Vray 6 GPU , 3ds max 2023

[hermit.crab]

Maybe the base shader is reflective? Best attach a simplified version of the scene here (or send it) so we can take a look.