Ok, so two links that could be useful. The first is for the issue of objects rendering black behind translucent glass.
It seems to be an issue of the inner face of the glass reflecting the interior meshes and their materials back at them with the shadow being solid black (a few different causes of solid black shadows from RT translucency). It could be something else, though, so I suggest trying a change based on the postings in the thread linked above.
The second link is for a series of fixes that may or may not help with other ray tracing issues. It might also help in understanding what’s involved in the ray tracing reflections and translucency dynamics, and provides code snippets and how to modify them to correct for errors.