If you are using Reality 4.1 and you experienced black glass when you are rendering it might be that you are using Extra Boost with multiple glass layers.
The figure above, for example, cannot be rendered with Extra Boost because each glass has a thickness and so there are four layers of materials that the light has to go through for each drinking glass or bottle. Extra Boost is configured to go fast but, in order to do so, it has to take some shortcuts. One of those shortcuts is a limit on the number of layers of glass a light ray can traverse.
In the future it will be possible to change that limit and adapt it to complex scenes with many layers of glass, but for now, if you see black glass rendering while the color of the glass is different, disable Extra Boost and use the standard CPU or GPU acceleration.