vtctldclient backup not working with defined VitessBackupStorages in cluster

I run

./vtctldclient --server 192.168.100.103:31487 Backup --allow-primary zone1-30573399

I get:

E0914 01:23:16.047192 3349604 main.go:56] rpc error: code = Unknown desc = TabletManager.Backup on zone1-0030573399 error: unable to get backup storage: no registered implementation of BackupStorage: unable to get backup storage: no registered implementation of BackupStorage

However, in the cluster spec I have defined a hostpath for the backups - and I can see it show up in VitessBackupStorages

apiVersion: planetscale.com/v2
kind: VitessBackupStorage
metadata:
  creationTimestamp: '2023-09-14T00:52:24Z'
  generation: 1
  labels:
    backup.planetscale.com/location: ''
    planetscale.com/cluster: example
  managedFields:
    - apiVersion: planetscale.com/v2
      fieldsType: FieldsV1
      fieldsV1:
        f:metadata:
          f:labels:
            .: {}
            f:backup.planetscale.com/location: {}
            f:planetscale.com/cluster: {}
          f:ownerReferences:
            .: {}
            k:{"uid":"272e7a69-a91f-4196-ad2d-8930c88c2715"}: {}
        f:spec:
          .: {}
          f:location:
            .: {}
            f:volume:
              .: {}
              f:hostPath:
                .: {}
                f:path: {}
                f:type: {}
      manager: vitess-operator
      operation: Update
      time: '2023-09-14T00:52:24Z'
    - apiVersion: planetscale.com/v2
      fieldsType: FieldsV1
      fieldsV1:
        f:status:
          .: {}
          f:observedGeneration: {}
      manager: vitess-operator
      operation: Update
      subresource: status
      time: '2023-09-14T00:53:06Z'
  name: example-90089e05
  namespace: vitess
  ownerReferences:
    - apiVersion: planetscale.com/v2
      blockOwnerDeletion: true
      controller: true
      kind: VitessCluster
      name: example
      uid: 272e7a69-a91f-4196-ad2d-8930c88c2715
  resourceVersion: '233908598'
  uid: 24068990-be71-49b5-ad17-773f581170a9
spec:
  location:
    volume:
      hostPath:
        path: /mnt/minio-store/vitess-backups
        type: Directory
status:
  observedGeneration: 1

Start by reproducing the vtctldclient Backup command and inspecting how the VitessBackupStorage resource with a hostPath is handled by the operator. Trace why the configured storage is not registered, then verify that the same backup command succeeds using the defined storage.