The glass transparency behavior will be improved in the upcoming version. For reflection correctness, ensure to have the rendering quality at least to "High".
So I'm in the newer version 18.104.22.168 and I'm still having the same issue, but with a slightly different issue.
I'm trying to make realistic looking lights. So I thought I model the lens and then model the light source above it. I'm trying to make a lens that would be translucent so you get a more diffused light from the light source material above it using a material with self-illumination. But I at 5% transparent the lens material just goes solid. And you can't really get the diffuse light look. Wonder if the updates that were done were supposed to fix this issue or not.