Kubernetes v1.21.2: 'selfLink was empty, can't make reference' - kubernetes

Question

I get this log error for a pod like below but I updated kubernetes orchestrator, clusters, and nodes to kubernetes v1.21.2. Before updating it, they were v1.20.7. I found a reference that from v1.21, selfLink is completely removed. Why am I getting this error? How can I resolve this issue?
error log for kubectl logs (podname)
...
2021-08-10T03:07:19.535Z INFO setup starting manager
2021-08-10T03:07:19.536Z INFO controller-runtime.manager starting metrics server {"path": "/metrics"}
E0810 03:07:19.550636 1 event.go:247] Could not construct reference to: '&v1.ConfigMap{TypeMeta:v1.TypeMeta{Kind:"", APIVersion:""}, ObjectMeta:v1.ObjectMeta{Name:"controller-leader-election-helper", GenerateName:"", Namespace:"kubestone-system", SelfLink:"", UID:"b01651ed-7d54-4815-a047-57b16d26cfdf", ResourceVersion:"65956", Generation:0, CreationTimestamp:v1.Time{Time:time.Time{wall:0x0, ext:63764161639, loc:(*time.Location)(0x21639e0)}}, DeletionTimestamp:(*v1.Time)(nil), DeletionGracePeriodSeconds:(*int64)(nil), Labels:map[string]string(nil), Annotations:map[string]string{"control-plane.alpha.kubernetes.io/leader":"{\"holderIdentity\":\"kubestone-controller-manager-f467b7c47-cv7ws_1305bc36-f988-11eb-81fc-a20dfb9758a2\",\"leaseDurationSeconds\":15,\"acquireTime\":\"2021-08-10T03:07:19Z\",\"renewTime\":\"2021-08-10T03:07:19Z\",\"leaderTransitions\":0}"}, OwnerReferences:[]v1.OwnerReference(nil), Initializers:(*v1.Initializers)(nil), Finalizers:[]string(nil), ClusterName:"", ManagedFields:[]v1.ManagedFieldsEntry{v1.ManagedFieldsEntry{Manager:"manager", Operation:"Update", APIVersion:"v1", Time:(*v1.Time)(0xc0000956a0), Fields:(*v1.Fields)(nil)}}}, Data:map[string]string(nil), BinaryData:map[string][]uint8(nil)}' due to: 'selfLink was empty, can't make reference'. Will not report event: 'Normal' 'LeaderElection' 'kubestone-controller-manager-f467b7c47-cv7ws_1305bc36-f988-11eb-81fc-a20dfb9758a2 became leader'
2021-08-10T03:07:21.636Z INFO controller-runtime.controller Starting Controller {"controller": "kafkabench"}
...
kubectl get nodes to show kubernetes version: the node that the pod is scheduled is aks-default-41152893-vmss000000
PS C:\Users\user> kubectl get nodes -A
NAME STATUS ROLES AGE VERSION
aks-default-41152893-vmss000000 Ready agent 5h32m v1.21.2
aks-default-41152893-vmss000001 Ready agent 5h29m v1.21.2
aksnpwi000000 Ready agent 5h32m v1.21.2
aksnpwi000001 Ready agent 5h26m v1.21.2
aksnpwi000002 Ready agent 5h19m v1.21.2
kubectl describe pods (pod name: kubestone-controller-manager-f467b7c47-cv7ws)
PS C:\Users\user> kubectl describe pods kubestone-controller-manager-f467b7c47-cv7ws -n kubestone-system
Name: kubestone-controller-manager-f467b7c47-cv7ws
Namespace: kubestone-system
Priority: 0
Node: aks-default-41152893-vmss000000/10.240.0.4
Start Time: Mon, 09 Aug 2021 23:07:16 -0400
Labels: control-plane=controller-manager
pod-template-hash=f467b7c47
Annotations: <none>
Status: Running
IP: 10.240.0.21
IPs:
IP: 10.240.0.21
Controlled By: ReplicaSet/kubestone-controller-manager-f467b7c47
Containers:
manager:
Container ID: containerd://01594df678a2c1d7163c913eff33881edf02e39633b1a4b51dcf5fb769d0bc1e
Image: user2/imagename
Image ID: docker.io/user2/imagename#sha256:aa049f135931192630ceda014d7a24306442582dbeeaa36ede48e6599b6135e1
Port: <none>
Host Port: <none>
Command:
/manager
Args:
--enable-leader-election
State: Running
Started: Mon, 09 Aug 2021 23:07:18 -0400
Ready: True
Restart Count: 0
Limits:
cpu: 100m
memory: 30Mi
Requests:
cpu: 100m
memory: 20Mi
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-jvjjh (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-jvjjh:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: Burstable
Node-Selectors: kubernetes.io/os=linux
Tolerations: node.kubernetes.io/memory-pressure:NoSchedule op=Exists
node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 23m default-scheduler Successfully assigned kubestone-system/kubestone-controller-manager-f467b7c47-cv7ws to aks-default-41152893-vmss000000
Normal Pulling 23m kubelet Pulling image "user2/imagename"
Normal Pulled 23m kubelet Successfully pulled image "user2/imagename" in 354.899039ms
Normal Created 23m kubelet Created container manager
Normal Started 23m kubelet Started container manager

Answer 1

Kubestone has had no releases since 2019, it needs to upgrade its copy of the Kubernetes Go client. That said, this appears to only impact the event recorder system so probably not a huge deal.