The l7-default-backend deployment gets reverted when I edit it - kubernetes

Question

I upgraded my GKE clusters to Kubernetes 1.5.6 a couple days ago. I used to be able to scale the l7-default-backend deployment to 3 replicas and increase the CPU resource limits, but now it seems my changes get reverted to their default of 1 replica and 10m CPU limit.
Interestingly enough, when I added the following:
nodeSelector:
cloud.google.com/gke-nodepool: default-pool
it was persisted no problem.
Here's the current deployment manifest:
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "4"
kubectl.kubernetes.io/last-applied-configuration: '{"kind":"Deployment","apiVersion":"extensions/v1beta1","metadata":{"name":"l7-default-backend","namespace":"kube-system","creationTimestamp":null,"labels":{"k8s-app":"glbc","kubernetes.io/cluster-service":"true","kubernetes.io/name":"GLBC"}},"spec":{"replicas":1,"selector":{"matchLabels":{"k8s-app":"glbc"}},"template":{"metadata":{"creationTimestamp":null,"labels":{"k8s-app":"glbc","name":"glbc"}},"spec":{"containers":[{"name":"default-http-backend","image":"gcr.io/google_containers/defaultbackend:1.0","ports":[{"containerPort":8080}],"resources":{"limits":{"cpu":"10m","memory":"20Mi"},"requests":{"cpu":"10m","memory":"20Mi"}},"livenessProbe":{"httpGet":{"path":"/healthz","port":8080,"scheme":"HTTP"},"initialDelaySeconds":30,"timeoutSeconds":5}}]}},"strategy":{}},"status":{}}'
creationTimestamp: 2017-03-23T23:30:12Z
generation: 9
labels:
k8s-app: glbc
kubernetes.io/cluster-service: "true"
kubernetes.io/name: GLBC
name: l7-default-backend
namespace: kube-system
resourceVersion: "40149922"
selfLink: /apis/extensions/v1beta1/namespaces/kube-system/deployments/l7-default-backend
uid: a9772d26-1020-11e7-b9a8-42010af001d0
spec:
replicas: 1
selector:
matchLabels:
k8s-app: glbc
strategy:
rollingUpdate:
maxSurge: 1
maxUnavailable: 1
type: RollingUpdate
template:
metadata:
creationTimestamp: null
labels:
k8s-app: glbc
name: glbc
spec:
containers:
- image: gcr.io/google_containers/defaultbackend:1.0
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 8080
scheme: HTTP
initialDelaySeconds: 30
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 5
name: default-http-backend
ports:
- containerPort: 8080
protocol: TCP
resources:
limits:
cpu: 10m
memory: 20Mi
requests:
cpu: 10m
memory: 20Mi
terminationMessagePath: /dev/termination-log
dnsPolicy: ClusterFirst
nodeSelector:
cloud.google.com/gke-nodepool: default-pool
restartPolicy: Always
securityContext: {}
terminationGracePeriodSeconds: 30
status:
availableReplicas: 1
conditions:
- lastTransitionTime: 2017-04-13T19:19:35Z
lastUpdateTime: 2017-04-13T19:19:35Z
message: Deployment has minimum availability.
reason: MinimumReplicasAvailable
status: "True"
type: Available
observedGeneration: 9
replicas: 1
updatedReplicas: 1
How can I scale the l7-default-backend successfully?