Many of my windows nodes are showing their fixed disk volumes (as expected) AND underlying volumes from the esxi host. Someone else asked about this 2 years ago with no answer here: Why it is showing the ESX host volumes in specific server details - Forum - Network Performance Monitor (NPM) - THWACK (solarwinds.com).
Under the hood the platform is trying to identify relationships between entities that it knows about so that you can utilize this info when troubleshooting. (Topology, Orion Maps, AppStack etc.) If the underlying volumes you mention are where the VM storage is allocated then what you are seeing would make sense. If what you mean is that these are unrelated local ESX host physical volumes with no VMs living on them then that might be a problem. You might want to open a ticket with support and ask them to run through it with you. If there is a bug or other issue that needs to be addressed, support can escalate that to engineering.
