[BUG]the last ordinal pod can not be online

[lancelot1989]

Using yaml's below to create a cluster.

apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: kafka2-ext-zk-descriptor
  namespace: default
spec:
  terminationPolicy: Delete
  # Specifies the name of the ClusterDefinition to use when creating a Cluster.
  # Note: DO NOT UPDATE THIS FIELD
  # The value must be `kafaka` to create a Kafka Cluster
  clusterDef: kafka
  # Specifies the name of the ClusterTopology to be used when creating the
  # Cluster.
  # - combined: combined Kafka controller (KRaft) and broker in one Component
  # - combined_monitor: combined mode with monitor component
  # - separated: separated KRaft and Broker Components.
  # - separated_monitor: separated mode with monitor component
  # Valid options are: [combined,combined_monitor,separated,separated_monitor,kafka2-external-zk]
  topology: kafka2-external-zk
  services:
    - name: bootstrap
      serviceName: bootstrap
      componentSelector: kafka-broker
      spec:
        type: ClusterIP
        ports:
          - name: kafka-client
            targetPort: 9092
            port: 9092
  componentSpecs:
    - name: kafka-broker
      componentDef: kafka27-broker
      serviceRefs:
        - name: kafkaZookeeper
          namespace: default
          serviceDescriptor: kafka-cluster-zookeeper-service
      tls: false
      replicas: 3
      env:
        - name: KB_BROKER_DIRECT_POD_ACCESS
          value: 'true'
        - name: KAFKA_HEAP_OPTS
          value: "-Xmx500m -Xms500m"
        - name: KB_KAFKA_ZK_SUB_PATH
          value: "test"   # set sub path to use for sharing zk, default value is $(CLUSTER_NAME), set empty string for root
      resources:
        limits:
          cpu: '0.5'
          memory: 0.5Gi
        requests:
          cpu: '0.5'
          memory: 0.5Gi
      volumeClaimTemplates:
        - name: data
          spec:
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 20Gi
        - name: metadata
          spec:
            storageClassName: null
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 5Gi
---
apiVersion: apps.kubeblocks.io/v1
kind: ServiceDescriptor
metadata:
  name: kafka-cluster-zookeeper-service
  namespace: default
spec:
  # Specifies the type or nature of the service.
  # Should represent a well-known application cluster type, such as {mysql, redis, zookeeper}.
  serviceKind: zookeeper
  # Represents the version of the service reference.
  serviceVersion: 3.8.5
  # Represents the endpoint of the service connection credential.
  endpoint:
    # your external zk endpoints here
    value: "zookeeper-cluster-zookeeper-0.zookeeper-cluster-zookeeper-headless.default:2181,zookeeper-cluster-zookeeper-1.zookeeper-cluster-zookeeper-headless.default:2181,zookeeper-cluster-zookeeper-2.zookeeper-cluster-zookeeper-headless.default:2181"
  # Represents the port of the service connection credential.
  port:
    value: "2181"

Using below yaml to do an OpsRequest to offline the last ordinal pod.

apiVersion: operations.kubeblocks.io/v1alpha1
kind: OpsRequest
metadata:
  generateName: offline-instance-
spec:
  clusterName: kafka2-ext-zk-descriptor
  horizontalScaling:
  - componentName: kafka-broker
    scaleIn:
      onlineInstancesToOffline:
      - kafka2-ext-zk-descriptor-kafka-broker-2
  type: HorizontalScaling

Using below yaml to do an OpsRequest to try to online the last ordinal pod.

apiVersion: operations.kubeblocks.io/v1alpha1
kind: OpsRequest
metadata:
  generateName: online-instance-
spec:
  clusterName: kafka2-ext-zk-descriptor
  horizontalScaling:
  - componentName: kafka-broker
    scaleOut:
      offlineInstancesToOnline:
      - kafka2-ext-zk-descriptor-kafka-broker-2
  type: HorizontalScaling

Then OpsRequest of online will stuck.

k get ops
NAME                           TYPE                CLUSTER                    STATUS    PROGRESS   AGE
offline-instance-6vkml         HorizontalScaling   kafka2-ext-zk-descriptor   Succeed   1/1        7m1s
online-instance-znk4k          HorizontalScaling   kafka2-ext-zk-descriptor   Running   0/1        6m10s

kafka2-ext-zk-descriptor-kafka-broker-2 can not be onlined.

k get pod
NAME                                      READY   STATUS    RESTARTS     AGE
kafka2-ext-zk-descriptor-kafka-broker-0   2/2     Running   0            8m43s
kafka2-ext-zk-descriptor-kafka-broker-1   2/2     Running   0            8m43s

Cluster's offlineInstances is cleaned but replicas does not increment.

k get cluster
NAME                       CLUSTER-DEFINITION   TERMINATION-POLICY   STATUS     AGE
kafka2-ext-zk-descriptor   kafka                Delete               Running    10m
k get cluster kafka2-ext-zk-descriptor -oyaml|grep -C5 replicas
    - name: KB_KAFKA_ZK_SUB_PATH
      value: test
    name: kafka-broker
    replicas: 2
    resources:
      limits:
        cpu: 500m
        memory: 512Mi
      requests:

KB version: v1.0.0-beta.21
K8S version: v1.30.4