After reinstalling vSphere, VMs in a Protection Group are missing or changed
By removing those VMs from a Protection Group once and re-selecting correct VMs will fix the issue.
Boomerang identifies VMs by the internal resource identifiers allocated by vSphere/ESX. Reinstalling vSphere or refreshing the inventory of vSphere will reset all the internal resource identifiers, and vSphere allocate new identifiers to resources. Due to this reason Boomerang cannot identify VMs in a Protection Group correctly.