Why attaching storage domain is failing with "duplicate key" error

Issue

• Attaching a storage domain is failing with below error in the engine log.

2017-10-25 06:21:56,624 ERROR [org.ovirt.engine.core.bll.storage.domain.AttachStorageDomainToPoolCommand] (org.ovirt.thread.pool-6-thread-9) [1598e81f] Command 'org.ovirt.engine.core.bll.storage.domain.AttachStorageDomainToPoolCommand' failed: CallableStatementCallback; SQL [{call insertunregistereddiskstovms(?, ?, ?, ?)}]; ERROR: duplicate key value violates unique constraint "idx_unregistered_disks_storage_to_vms_unique"

• Two VMs OVF configuration in the OVF_STORE was pointing to same disk even though the disks are not shared.