There are some models that are not filling in NRM_LineCard detail even though there is an EntityApp created.
Spectrum line card data requires each instance to have a serial number. If there is no serial number, Spectrum does not populate the line card data.
Release : 10.4.1
Component : Spectrum Discovery & Modeling
This is resolved in 20.2.3 (aka 10.4.2.1) version of Spectrum by editing the $SPECROOT/SS/.vnmrc file and add:
This allows Chassis data to be built without the serial # being populated.