When you rebalance linked-clone virtual machines, vCenter Server changes the filenames of View Composer persistent disks and disposable-data disks in linked clones that are moved to a new datastore.
The original filenames identify the disk type. The renamed disks do not include the identifying labels.
An original persistent disk has a filename with a user-disk label: desktop_name-vdm-user-disk-D-ID.vmdk.
An original disposable-data disk has a filename with a disposable label: desktop_name-vdm-disposable-ID.vmdk.
After a rebalance operation moves a linked clone to a new datastore, vCenter Server uses a common filename syntax for both types of disks: desktop_name_n.vmdk.