Why I see tcp retransmission when telnet one pod to another?

[vsfomin]

I have deployed two pods named swiss-army-knife in my cluster in two namespaces, and on each pod, I’m listening on TCP port 9000 using nc -l -p 9000. When I connect from one pod to another using telnet, I receive the message:
Pod name: swiss-army-knife-d88d4f945-dhggp, Namespace: swiss-army-1, Container: swiss-army-knife-9000— so everything works fine.
10.233.69.233 - IP of Swiss-army-knife in swiss-army-2 namespace, 10.233.69.59 - pod ip in swiss-army-1 namespace
However, in the traffic dump, I observe many TCP retransmits. Could this indicate a misconfiguration in Cilium, or is it more likely caused by how netcat/telnet behave in my case?

Example of one Pod in namespace swiss-army-2

apiVersion: apps/v1
kind: Deployment
metadata:
  name: swiss-army-knife
  namespace: swiss-army-2
  labels:
    app: swiss-army-knife
spec:
  replicas: 1
  selector:
    matchLabels:
      app: swiss-army-knife
  template:
    metadata:
      labels:
        app: swiss-army-knife
    spec:
      nodeSelector:
        kubernetes.io/hostname: dev-k8s-0002
      containers:
      - name: swiss-army-knife-9000
        image: leodotcloud/swiss-army-knife:latest
        imagePullPolicy: IfNotPresent
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        - name: CONTAINER_NAME
          value: swiss-army-knife-9000

        command: ["/bin/sh", "-c"]
        args:
          - |
            while true; do
              echo "Pod name: $POD_NAME, Namespace: $POD_NAMESPACE", Container: $CONTAINER_NAME | nc -l -p 9000;
            done &
            /bin/sleep 3650d   
---
apiVersion: v1
kind: Service
metadata:
  name: swiss-army-knife
  namespace: swiss-army-2
spec:
  selector:
    app: swiss-army-knife
  ports:
    - protocol: TCP
      name: tcp-test-two
      port: 9000
      targetPort: 9000