I’m not sure if this issue was reported already, but I’m seeing a problem when using the VrayMtlWrapper as a matte surface. The issue is described in the image attached, I’m not sure if one of my settings can be causing this.
As you can see the shadow I was supposed to get is very soft (almost look like Ambient Occlusion, but only the “Shadows” option I get this effect) but as you can see when applying the VrayMtlWrapper I get this weird hard shadow that is not even being cast by the light, since the objects are in shadow:
Can you backtrack if this really is a shadow, and if yes which light is causing it?
Could you also set the reflection, refraction and GI amount in the matte properties to 0 in order to eliminate possible issues.
Do you get the same issue if instead of a MaterialWrapper you define the matte object in the V-Ray object properties instead?
Best you send the scene to support@chaosgroup.com so we can take a look. Mention this thread in the e-mail, along with your V-Ray and host platform versions.