Deleting an IPv4 or IPv6 CIDR directly in NSX-T (and not replacing it with another) does not remove it in the corresponding Network within Aria Automation
VMware NSX-T Data Center
VMware NSX
This is an identified limitation of Aria Automation data collection: it will pick up additions and edits to CIDRs but not removals. The issue is present up to at least 8.17.0, with the fix planned for a future release.
Note that the CIDR can be removed in NSX only if there are no ranges with assigned IP addresses.
Once a replacement v4 or v6 CIDR is added to that segment in NSX, data collection will pick up the new one.
The CIDR can be removed in Aria Automation by editing the network:
Any admin looking to remove IPv4 or IPv6 connectivity a segment in NSX should match this removal in Aria Automation > Infrastructure > Networks.