After a VMware Cloud Foundation (VCF) instance has been decommissioned and removed from the VCF Operations (formerly Aria Operations) integration, the management domain and workload domain vCenters automatically reappear in the integration list overnight, even though the environments no longer exist.
VCF Operations 9.x
VCF SDDC 9.x
To resolve this issue ensure that all virtual appliances associated with the decommissioned VCF instance (SDDC Manager, vCenters, NSX Managers) are fully powered off. This prevents any background heartbeats or discovery processes from triggering a re-registration.