VM Placement Policies can be based on VM Groups defined in vCenter.
If the Name of the VM Group changes in vCenter this will lead VMs managed by Cloud Director to be unable to edit/modify/remove VM Placement policy
Cloud Director
By changing VM Group name in vCenter. This breaks the relation between vCenter VM Groups and Cloud Director VM Placement Policy
There may be a way to resolve this through updating the Cloud Director DB but it is unknown currently.
What is recommended is the following:
1. Create a New VM Group in vCenter with the correct name
2. Create New VM Placement Policy in Cloud Director
3. Move VMs to the New VM Placement Policy