If you use inheritFrom to inherit the parent template, why does label not take effect?

Jenkins setup:

Jenkins: 2.387.2
OS: Linux - 5.15.0-89-generic
Java: 11.0.12 - Oracle Corporation (Java HotSpot(TM) 64-Bit Server VM)
kubernetes:3937.vd7b_82db_e347b_
kubernetes-client-api:6.4.1-215.v2ed17097a_8e9
kubernetes-credentials:0.10.0

Manage Jenkins → Manage Nodes and Clouds → Configure Clouds The parent template is configured with label values:

use inheritFrom to inherit the parent template:

pipeline {
  agent {
    kubernetes {
      cloud 'kubernetes'
      inheritFrom: 'defined-slave-labels'
      yamlMergeStrategy:@merge()
      ......
    }
  }
......

Generated pod template:

---
apiVersion: "v1"
kind: "Pod"
metadata:
  annotations:
    buildUrl: "http://172.26.88.5:8090/job/k8s-test/92/"
    runUrl: "job/k8s-test/92/"
  labels:
    jenkins: "slave"
    jenkins/label-digest: "fe5e791cc781a1709aca3c4a82ff67621d8d19c2"
    jenkins/label: "k8s-test_92-zvj43"
......

The parent template defines the tag value as jenkins-agent. Why does it not take effect.