When attempting to migrate VM's between clusters in the same vCenter using cross vCenter option along with Keep VMs on the source vCenter Server (performs a VM clone operation), it fails with an error "Entity VmCloneSpec.folder cannot be null".
vCenter server 7.x
vCenter server 8.x
When attempting to use cross-vCenter vMotion with a clone operation between clusters within the same vCenter, the folder options won't populate, resulting in the error: "Entity VmCloneSpec.folder cannot be null."
When performing a cross-vCenter vMotion between clusters, the folder options will be available.
The Cross vCenter vMotion option should be used to migrate VMs between different vCenters, not between clusters within the same vCenter.
To migrate VMs between clusters within the same vCenter, use Storage vMotion and Compute vMotion. (If need to clone the virtual machine, clone it manually).