, thanks for letting us know of your requirement, I'm curious why the VDVS volumes would need to be migrated. Storage vmotion applies to VMs where the VM's VMDKs (dependent disks) are migrated to a target datastore. The VDVS volumes are completely separate from VM disks and are managed wholly by the plugin and via the admin CLI on the ESX host. The datastores where the VDVS volumes get placed is also related but not limited to the datastore where the VM is located (although that's the default location).
I'd like to know the use case that requires migrating the VDVS volumes to a different location. The VDVS volumes are all tracked in a config database (if initialized) and that data would go stale if the volumes are migrated using the vSphere client. Possibly a config database isn't initialized in your setup and hence the issues isn't observed.