How to solve the FailedScheduling error caused by k8s webhook

Question

I have a project that needs to intercept and add some data after pod scheduling, so I use the following webhook configuration interception

apiVersion: admissionregistration.k8s.io/v1
kind: MutatingWebhookConfiguration
metadata:
  name: mutationpod
...
...
  rules:
  - operations: ["CREATE"]
    apiGroups: [""]
    apiVersions: ["v1"]
    resources: ["pods/binding"]

Then modify the pod

func (p *PodMutate) Handle(ctx context.Context, req admission.Request) admission.Response {
    binding := &corev1.Binding{}

    _ := p.decoder.Decode(req, binding)

    pod := &corev1.Pod{}
    if err = p.Client.Get(ctx , types.NamespacedName{Namespace: binding.Namespace, Name: binding.Name}, pod); err != nil {
        log.Error(err)
        return admission.Allowed("")
    }

    // modify pod code
    ...
    ...
    p.Client.Update(ctx , pod)

    return admission.Allowed("")
}

During the testing phase, it was found that some pods will have a FailedScheduling event

Events:
  Type     Reason            Age   From               Message
  ----     ------            ----  ----               -------
  Warning  FailedScheduling  41s   default-scheduler  AssumePod failed: pod 138cef2c-029b-407f-86c2-e1231eca9233 is in the cache, so can't be assumed
  Normal   Scheduled         41s   default-scheduler  Successfully assigned default/nginx-deployment-f8c77cd9d-m8zvd to <nodeName>
  Normal   Pulled            40s   kubelet            Container image "nginx:1.17.1" already present on machine
  Normal   Created           40s   kubelet            Created container nginx
  Normal   Started           40s   kubelet            Started container nginx

I'm confused as to why the interception of pods/binding causes other schedulers to schedule. How can I modify to avoid this exception

I really appreciate any help with this.

Note: I use multiple schedulers to keep high availability, but I use the leader mechanism(--leader-elect=true)
Official examples for reference