Glass refraction issue

Hello!

I´m having some problem with glass and refraction.

I have create glass panels (simple box with chamfered edges) and I get some weird black stuff on the furniture behind the glass.
When I enable “thin (no refraction)” the problem goes away.

Why is that?

Would be happy if someone could shed some light on this :smiley:

I have attached an image with and without the problem and material settings.

Thank you for the information! :smiley: Looking forward for it to be fixed!