We have a vRNI deployment on a Stretched Cluster Environment. The issue we faced is regarding vSAN Witness Appliances that add up to total number of licensing.
Had the same issue in vROPS but could easily exclude those Witness Appliances. Is there a way to exclude them in vRNI licensing page?
If you do not have version 6.0 configured, try to change the permissions to No Access for the user you are using to connect to vCenter Server from vRNI and apply it to the Witness Host.
Sometimes I use this as a workaround with some other solutions to not get some objects populated but never tested with vRNI and maybe it works.