Cloned virtual machine with same UUID can cause a Foglight topology churn if Infrastructure (IC) agents are monitoring those virtual machines.
IC agent gets the Windows system ID by using this query
"Select UUID from Win32_ComputerSystemProduct"
in WMI namespace: \root\cimv2. If virtual machines have been cloned with BIOS UUID and then monitored by VMware performance agent and Infrastructure agent, Foglight will treat the different virtual machine as a single host which causes the churn.
On Unix machines we get the systemID in Foglight from the file "etc/machine-id".
Make sure that each cloned VMWare is having a unique bios.uuid/machine ID. The bios.uuid can be found in the *.vmx file.
The VMWare knowledge base provides the steps to change the bios.uuid in article 1002403. If further help is needed, please contact the VMWare support team.