kyverno: [BUG] Background scan doesn't work

Software version numbers

• Kubernetes version: 1.19.10
• Kyverno version: v1.4.2

Describe the bug Background scan doesn’t work.

To Reproduce Applying:

apiVersion: v1
kind: Namespace
metadata:
  name: test

Then:

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: test
  namespace: kyverno
spec:
  background: true
  validationFailureAction: audit # even with enforce
  rules:
    - name: test
      match:
        any:
          - resources:
              kinds:
                - Namespace
      validate:
        message: "Metadata label 'name' is required."
        pattern:
          metadata:
            labels:
              name: "?*"

Doesn’t raise any error in clusterpolicyreport.

Expected behavior This should raise an error in a clusterpolicyreport because of background: true.