- Manual change of a failed job condition status to False does not result in duplicate conditions ([#110292](https://github.com/kubernetes/kubernetes/pull/110292), [@mimowo](https://github.com/mimowo)) [SIG Apps]
- OpenAPI will no longer duplicate these schemas:
  - io.k8s.apimachinery.pkg.apis.meta.v1.DeleteOptions_v2
  - io.k8s.apimachinery.pkg.apis.meta.v1.ObjectMeta_v2

- Fixed a regression in default configurations, which enabled PodDisruptionConditions by default, 
  that prevented the control plane's pod garbage collector from deleting pods that contained duplicated field keys (env. variables with repeated keys or container ports). ([#121380](https://github.com/kubernetes/kubernetes/pull/121380), [@mimowo](https://github.com/mimowo)) [SIG Apps, Auth, Scheduling and Testing]

- Fixed a regression in default configurations, which enabled PodDisruptionConditions by default, 
  that prevented the control plane's pod garbage collector from deleting pods that contained duplicated field keys (env. variables with repeated keys or container ports). ([#121379](https://github.com/kubernetes/kubernetes/pull/121379), [@mimowo](https://github.com/mimowo)) [SIG Apps, Auth, Node, Scheduling and Testing]

- Duplicate owner reference entries in create/update/patch requests now get deduplicated by the API server. The client sending the request now receives a warning header in the API response. Clients should stop sending requests with duplicate owner references. The API server may reject such requests as early as 1.24. ([#96185](https://github.com/kubernetes/kubernetes/pull/96185),...

- Kubeadm: fixed the bug that `kubeadm certs generate-csr` command does not remove duplicated SANs ([#107982](https://github.com/kubernetes/kubernetes/pull/107982), [@SataQiu](https://github.com/SataQiu))

### SIG Storage

- The AllowedTopologies field inside StorageClass is now validated against set and map semantics. Specifically, there cannot be duplicate TopologySelectorTerms, MatchLabelExpressions keys, or TopologySelectorLabelRequirement Values. ([#66843](https://github.com/kubernetes/kubernetes/pull/66843), [@verult](https://github.com/verult))

- Fixed a bug which kubectl would emit duplicate warning messages for flag names that contain an underscore and recommend using a nonexistent flag in some cases. ([#103852](https://github.com/kubernetes/kubernetes/pull/103852), [@brianpursley](https://github.com/brianpursley))

- EndpointSlice controllers are less likely to create duplicate EndpointSlices. ([#100103](https://github.com/kubernetes/kubernetes/pull/100103), [@robscott](https://github.com/robscott)) [SIG Apps and Network]

* kubectl and client-go now detect duplicated names for user, cluster and context when loading kubeconfig and report this condition as an error.  ([#60464](https://github.com/kubernetes/kubernetes/pull/60464), [@roycaihw](https://github.com/roycaihw))

- Fixed a regression in default 1.26 configurations, which enabled PodDisruptionConditions by default, 
  that prevented the control plane's pod garbage collector from deleting pods that contained duplicated field keys (env. variables with repeated keys or container ports). ([#121381](https://github.com/kubernetes/kubernetes/pull/121381), [@mimowo](https://github.com/mimowo)) [SIG Apps, Auth, Scheduling and Testing]