Missing ESXi hosts lacked active license entitlement/capacity within VCF Operations
VCF Operations 9.x
When VCF Operations exceeds its licensed capacity, newly added or unentitled objects are discovered but are filtered out of certain dashboard views and active metric processing.
Using the Global Search bar and navigating to Environment > Inventory > vCenter Server > Host System confirmed the hosts were discovered and present in the database. Because they were in the inventory but missing from the specific "Fleet Management" view, the issue was isolated to UI filtering and capacity limits rather than a collection failure.
To resolve the issue: Sync or update the licensing usage in VCF Operations to ensure all discovered hosts are fully entitled.