Virtual machine storage migration plan is stuck in pending status with ConflictingPVCMappings error

Issue

Storage migrations for any Virtual Machine within a specific namespace remain stuck in a Pending status. The MigMigration resource reports a ConflictingPVCMappings critical condition with PvNameConflict :

# oc get migmigration migmigration-nw6t -n openshift-migration -o yaml |yq '.status'
conditions:
  - category: Critical
    lastTransitionTime: "2025-12-16T18:00:08Z"
    message: Source PVCs [] are mapped to destination PVCs which result in conflicts. Please ensure that each source PVC is mapped to a distinct destination PVC in the Migration Plan.
    reason: PvNameConflict
    status: "True"
    type: ConflictingPVCMappings