The endPort for multinetworkpolicy can be defined when endport is smaller than the port field.

build 4.19, openshift/cluster-network-operator#2668  

Always

$ cat test_mnp_ingress_endport.yaml
apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: ingress-policy
  annotations:
    k8s.v1.cni.cncf.io/policy-for: tenant1-secondary-layer2
spec:
  podSelector: {}
  policyTypes:
    - Ingress
  ingress:
    - from: []
      ports:
        - protocol: TCP
          port: 32000
          endPort: 31900$ oc create -f test_mnp_ingress_endport.yaml
multinetworkpolicy.k8s.cni.cncf.io/ingress-policy created
$ oc get multi-networkpolicy ingress-policy -o yaml
apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  annotations:
    k8s.v1.cni.cncf.io/policy-for: tenant1-secondary-layer2
  creationTimestamp: "2025-04-08T20:42:57Z"
  generation: 1
  name: ingress-policy
  namespace: blue-network
  resourceVersion: "114630"
  uid: 755f6156-a119-41ad-8635-c9fcf9b07eb2
spec:
  ingress:
  - from: []
    ports:
    - endPort: 31900
      port: 32000
      protocol: TCP
  podSelector: {}
  policyTypes:
  - Ingress

Multinetworkpolicy is created without errors 

Multinetworkpolicy will not be created and the error should be displayed in the console. 

Check features restrictions in https://kubernetes.io/docs/concepts/services-networking/network-policies/#targeting-a-range-of-ports