Welcome to the Community - I believer what you vSphere cluster is configured for DRS - DRS (Distributed Resource Scheduler) can is technology that ensures your VMs will receive the sufficient level of resources - this is done during start up and while the VM is running - when the VM starts the host with most available resources is selected for the VM to start on and then while it is running it will vMotion the VM to a host with sufficeint resources - so your vCenter VM could have moved either at start up or while running -
NOw are you able to access your vCenetr viw the vSphere CLient?
