Please see these two threads for context:
It turns out that many of the 3ds Max models that cannot be Fully Exported are based on V-Ray or Corona. This is fine. At this point I only care about the plain vanilla, scan line rendered.
I just found an excellent illustration of the shortcoming.
The number of maps in the last column is always zero, no matter what I do. No further explanation is provided.
ps: I downloaded that model most likely from CGTrader. Can’t locate it again in their web site.