Used and Available cores are blank in SDDC Manager under License Tab. Only total cores are visible.
Only total cores are visible from NSX Manager.
VMware Cloud Foundation 5.2.x
This behavior is completely expected by design and does not represent a product defect or functional misconfiguration.
It is expected to see the Used and Available columns left blank for your VMware NSX Data Center license in this view.
vCenter Server and vSAN are natively managed and tracked directly by the vCenter license service, which allows vCenter to calculate and display exactly how many servers or CPU/Core units are used and available.
VMware NSX, however, is an independent solution repository. When you add an NSX license to vCenter, vCenter acts merely as a centralized repository to store and pass the key along to other components. Because NSX calculates its own capacity and usage within its own management plane, vCenter does not actively track or compute the "Used" or "Available" metrics for it.