Global illumination shadows on a matte

[TheLooopCGI]

Is it possible that shadows of objects created by global illumination is not correct on matte materials?

If I make a simple test and create a plane on which is sitting a sphere and light the scene with environment light, the shadow looks quite different when I turn the matte property of the plane on/off...

EDIT: I was testing this a bit and it seems it's the Irradiance map causing problem - specificaly the Detail Enhancement option. When I turn it off then the shadow on a non-matte plane is the same as when the plane is matte. Also when I change the GI engine to brute force it's okay. So is the Detail Enhancement algorithm ignoring a matte plane?

[TheLooopCGI]

Vlado could you please explain what is going on with this and if there is a possibility to have a fix or workaround?

Thanks!

[TheLooopCGI]

Hmm, nobody using mattes and global illumination these days eh?

[vlado]

I don't think the detail enhancement will work well with matte objects; it would be better to either turn it off, or use brute force GI in that case.

Best regards,
Vlado