How determine if VM in Vcenter (6.7) is Managed by Vcloud Director (9.5)

I used to have a script which connected to Viirtual Center and listed all VMs which are not managed by vcloud director. This worked well for Vcenter 6.5 and vcloudDirector 9.1 using the ManagedBy Attribute in the class VMware.Vim.VirtualMachineConfigInfo
After the Update to 6.7 and 9.5 this was unfortunately changed, and the managedby Attribute is now empty.... does anyone know how to determine between a VM managed by vcloud director and which is not? I cannot find any attribute which contains that part of information.