It appears to me that there is a problem with the new Nested Dielectrics. I have made a quick test scene with a Dark Green Glass shape, with something akin to Red Wine inside (Geometry of the wine extended to overlap the glass inside polygons). As I have always done, I give the Glass a shallow Transmission Depth and the Wine a relatively larger Transmission Depth. I will attach 3 screen grab renders of the Glass by itself, the Wine by itself and another with the Wine in the Glass. As you can see the Wine basically disappears leaving only some specular details behind. I have a link to the C4D file as well if you want to check out. I would be curious to hear what you think of it and if I am doing something wrong or if it is a bug. BTW. I am using C4D R21. I have not tested it on other versions. Also this is using CPU ... if I use the GPU it looks like the render where Nested Dielectrics is turned off.
C4D R21.207, C4DtoA-3.2.1
Scene saved to Dropbox below.
https://www.dropbox.com/s/7d08asr1ba9cjx1/Dielectric_Nesting_TestScene.c4d?dl=0
Log file below
https://www.dropbox.com/s/77jfhi9yna3ly7p/LogFile.zip?dl=0
