When adding new values to a capi MachineSet's `.spec.selector.matchLabels` and `.spec.template.metadata.labels`, new Machines are created for the MachineSet but the old Machines become orphaned from the MachineSet.

 4.17.0-0.nightly-2024-08-08-013133   

    Always

1. Create a new cluster enable TechPreviewNoUpgrade
2. Edit one of the capi worker MachineSets to add a new label in the `.spec.selector.matchLabels` and `.spec.template.metadata.labels` 
3. Observe the Machines and MachineSet replica counts     

A new Machine is created which takes the new selector match label, and the old Machine becomes orphaned from the MachineSet. 
$ oc edit machineset capi-ms 
  replicas: 2
  selector:
    matchLabels:
      aaa: aaa
      cluster.x-k8s.io/cluster-name: zhsun-gcp89-bgdwh
      machine.openshift.io/cluster-api-cluster: zhsun-gcp89-bgdwh-invalid
  template:
    metadata:
      labels:
        aaa: aaa
        cluster.x-k8s.io/cluster-name: zhsun-gcp89-bgdwh
        machine.openshift.io/cluster-api-cluster: zhsun-gcp89-bgdwh-invalid

$ oc get machineset             
NAME      CLUSTER             REPLICAS   READY   AVAILABLE   AGE   VERSION
capi-ms   zhsun-gcp89-bgdwh   2          1       1           24m

$ oc get machine      
NAME            CLUSTER             NODENAME                                              PROVIDERID                                       PHASE     AGE     VERSION
capi-ms-f6hxz   zhsun-gcp89-bgdwh                                                                                                          Pending   5m12s
capi-ms-v7jhh   zhsun-gcp89-bgdwh   capi-ms-v7jhh.us-central1-a.c.openshift-qe.internal   gce://openshift-qe/us-central1-a/capi-ms-v7jhh   Running   5m46s
capi-ms-wptvh   zhsun-gcp89-bgdwh   capi-ms-wptvh.us-central1-a.c.openshift-qe.internal   gce://openshift-qe/us-central1-a/capi-ms-wptvh   Running   24m

MachineSet selector is immutable    

Mapi bug https://bugzilla.redhat.com/show_bug.cgi?id=2005052

If only edit `.spec.selector.matchLabels` like below, is not allowed.
$ oc edit machineset capi-ms
  selector:
    matchLabels:
      aaa: aaa
      cluster.x-k8s.io/cluster-name: zhsun-gcp89-bgdwh
      machine.openshift.io/cluster-api-cluster: zhsun-gcp89-bgdwh-invalid

# machinesets.cluster.x-k8s.io "capi-ms" was not valid:
# * spec.template.metadata.labels: Invalid value: map[string]string{"cluster.x-k8s.io/cluster-name":"zhsun-gcp89-bgdwh", "machine.openshift.io/cluster-api-cluster":"zhsun-gcp89-bgdwh"}: must match spec.selector "aaa=aaa,cluster.x-k8s.io/cluster-name=zhsun-gcp89-bgdwh,machine.openshift.io/cluster-api-cluster=zhsun-gcp89-bgdwh-invalid"