Why are raytraced shadows from glass so solid?

I like shadows in new unreal 4.22, using raytracing
But why are shadows from glas as if they are casted from solid wall and not from transparent glass?


Translucent ray traced shadows are currently not implemented. Glass in your screenshot simply behaves as an opaque surface. Support for translucent shadows is on our radar, but keep in mind that it will come with a potentially significant performance cost.