Issues with primatte studio

Hi all
just trying to use primatte in Vegas 19 on a recent green screen production.
Source is 4k mxf in 4.2.2. from a Sony FS7 in standard 709 mode.
I’m watching this tutorial:

and run into a problem within the first steps.
I loaded primatte into the custom composite OK. Then, as advised, use auto analyze, but what happens next is not at all what I see in the tutorial:

Matte looks like this:

I should mention that there is a white media generator underneath, and some of the sliders / functions are greyed out, no idea how to activate them. This is a clean green screen with proper lighting - I can’t seem to understand what primatte can’t detect here. I tried moving the sample point - no effect. Of course there will also be a rectangle mask around the person to eliminate all the unused space.
it looks like BCC is keying the person instead of the green screen.
What am I missing here?
Thanks for any help!

Hi there.

Can you send me a frame from the clip please? ( I’ll give it a shot. I’m sure that Primatte can generate a perfect key on this shot in about a minute and I can send you a preset so that you can see how it works.