Argo CD shows two items from linkerd (installed by Helm) are being out of sync. The warnings are caused by the optional preserveUnknownFields: false in the spec section:

trafficsplits.split.smi-spec.io

serviceprofiles.linkerd.io

But I'm not able to figure out how to ignore the difference using ignoreDifferences in the Application manifest. The /spec/preserveUnknownFields json path isn't working. Is it because the field preserveUnknownFields is not present in the left version?

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: linkerd
  namespace: argocd
spec:
  destination:
    namespace: linkerd
    server: https://kubernetes.default.svc
  project: default
  source:
    chart: linkerd2
    repoURL: https://helm.linkerd.io/stable
    targetRevision: 2.10.1
 syncPolicy:
    automated: {}
  ignoreDifferences:
     - group: apiextensions.k8s.io/v1
       name: trafficsplits.split.smi-spec.io
       kind: CustomResourceDefinition
       jsonPointers:
         - /spec/preserveUnknownFields
     - group: apiextensions.k8s.io/v1
       name: trafficsplits.split.smi-spec.io
       kind: CustomResourceDefinition
       jsonPointers:
         - /spec/preserveUnknownFields

As per documentation, I think you have to use apiextensions.k8s.io not apiextensions.k8s.io/v1.