HPA spawns too many pods

Question

This is my hpa configuration.

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: customer-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: customer
  minReplicas: 2
  maxReplicas: 8
  metrics:
    - type: Resource
      resource:
        name: memory
        target:
          type: Utilization
          averageUtilization: 70

The assigned memory and cpu limits for the deployment are like below.

resources:
  requests:
    memory: 660Mi
    cpu: 100m
  limits:
    memory: 860Mi
    cpu: 500m

The number of replicas of the deployment is like below.

replicas: 2

When I listed the hpa, it is showed like below.

NAME                     REFERENCE                           TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
customer-service-hpa     Deployment/customer-service         46%/70%         2         8         4          36d

When I deploy the deployment and run

kubectl top pods

the output is like below.

customer-9fddb6649-24r88                   7m           294Mi
customer-9fddb6649-6x97x                   7m           305Mi
customer-9fddb6649-cpg6g                   56m          309Mi
customer-9fddb6649-ldbb2                   12m          314Mi

Eventhough the load is low, initially pod count is 4. But the given minimum pod is 2.

Is there any issue in deployment files?