Bug: `error setting new revision manifests: cache: key is missing` warn on webhook refresh

[JeongPope]

Checklist:

• I've searched in the docs and FAQ for my answer: https://bit.ly/argocd-faq.
• I've included steps to reproduce the bug.
• I've pasted the output of argocd version.

Describe the bug
When using multi sources (spec.sources) and a Git push webhook triggers an Argo CD refresh, the following warning appears in argocd-server logs:

Failed to store cached manifests of previous revision for app '<APP_NAME>': error setting new revision manifests: cache: key is missing

To Reproduce

• Repo server: useEphemeralHelmWorkingDir=false
• Application manifest

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  annotations:
    argocd.argoproj.io/manifest-generate-paths: foo/bar
  name: my-app
  namespace: my-app
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  project: default
  sources:
    - repoURL: https://github.com/org/repo.git
      targetRevision: master
      ref: values
    - repoURL: https://chartmuseum.hello.world
      chart: common
      targetRevision: 2.3.4
      helm:
        releaseName: my-app
        valueFiles:
        - $values/foo/bar/values.yaml
  destination:
    server: https://kubernetes.default.svc
    namespace: my-app
  syncPolicy:
    automated:
      enabled: true
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true

Steps:

1. Push a commit that modifies only foo/bar/values.yaml in the Git repo.
2. Observe that the Argo CD webhook triggers a refresh.
3. See warning log on argocd-server.

Expected behavior
When valueFiles change (only within manifest-generate-paths), the webhook should trigger application refresh (which it does), no warning logs.

Version

• Helm chart : 8.3.6
• App version : 3.1.5

Logs

Failed to store cached manifests of previous revision for app '<APP_NAME>': error setting new revision manifests: cache: key is missing