Problem with view settings in Rendered view

Before if I did Costum Preview Material in Grasshopper and in Rendered view in Rhino it looked like this. (a bit seen trough like glassy)

Now it looks like this… (untransparant) But I didn’t change anything in Grasshopper.

However in Artistic view it still looks like the first image but then the surrounding buildings look different. Like it’s again seen trough and glassy, but now the whole thing is darker.

Someone that can help me??

Thank you!!

Hey Brecht -
Could you post the gh file with (a few of) those objects internalized?
Also, please run the Rhino SystemInfo command and copy-paste the result here.