Need to manually delete old pvc for multiple migrations

CNV 4.18.0
MTC 1.8.5-9

Always

1. Create a VM
2. Create a migplan
3. Stage the plan
4. Stage the plan again after step3 succeed

step3:
$ oc get pvc
NAME                            STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS                                 VOLUMEATTRIBUTESCLASS   AGE
cirros-dv-source-ocs            Bound    pvc-1fa90eec-3fa9-4dc3-9174-ee08e3a94dd7   1Gi        RWX            ocs-storagecluster-ceph-rbd                  <unset>                 49m
cirros-dv-source-ocs-mig-zwgq   Bound    pvc-2eb96850-4b63-4a6b-bebd-6e830e5b085c   1Gi        RWX            ocs-storagecluster-ceph-rbd-virtualization   <unset>                 12m

step4, failed to stage and got 
  Warning  ConflictingPVCMappings  2m48s (x102 over 7m46s)  migmigration_controller  Source PVCs [mig-vm/cirros-dv-source-ocs-mig-zwgq] 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.

Should be able to automatic stage multiple times without manually deleting the old pvc

Need to delete the old pvc and then trigger the stage again