Shadowcatcher mtl giving light?

Hi

For product shots I often use a HDRI with a (corona color) Shadowcatcher ground for the shadow on a plain background. Because of the great control of background color.

I noticed something strange, did some tests and it looks like the shadowcatcher mtl gives light??
I have no idea for how long this is, but it doesn’t look good..

What are your thoughts on it, or does someone has a solution?

Attached a simple scene with a shadowcatcher ground, a basic corona mtl ground and my results.
Shadowcatcher_test.rar (275 KB)