Cannot get observed state at secret with empty data

[CsDenes]

What happened?

After creating a Kubernetes Secret with an empty data field, the observer fails with the following warning, and the Secret cannot be managed afterward. This issue appeared after enabling the -enable-server-side-apply.

cannot get observed state: failed calling ExtractInto for unstructured: unable to convert managed fields for provider-kubernetes/test-secret to unstructured, expected map, got <nil>

How can we reproduce it?

Create an object with the following manifest, where data field is specified but empty.

apiVersion: kubernetes.crossplane.io/v1alpha2
kind: Object
metadata:
  name: test-secret
spec:
  deletionPolicy: Delete
  forProvider:
    manifest:
      apiVersion: v1
      data:
      kind: Secret
      metadata:
        name: test-secret
        namespace: default
  managementPolicies:
  - '*'
  providerConfigRef:
    name: default

What environment did it happen in?

Crossplane version: v1.19.0
provider-kubernetes version: v0.18.0 (with --enable-server-side-apply)
Kubernetes version: v1.34.0