chown: changing ownership of '/home/postgres/pgdata/pgroot/data': Operation not permitted when using NFS

• Which image of the operator are you using? registry.opensource.zalan.do/acid/postgres-operator:v1.10.0
• Where do you run it? - Bare Metal K8s
• Are you running Postgres Operator in production? no
• Type of issue? [Bug report]

I just tried a minimal cluster:

helm repo add postgres-operator-charts https://opensource.zalando.com/postgres-operator/charts/postgres-operator -n postgres-operator
helm install postgres-operator postgres-operator-charts/postgres-operator -n postgres-operator
curl https://raw.githubusercontent.com/zalando/postgres-operator/master/manifests/minimal-postgres-manifest.yaml | kubectl apply -n postgres-operator -f -

The commands above work fine using EKS in AWS. But when I try to create it in bare-metal k8s, it throws permission errors:

chown: changing ownership of '/home/postgres/pgdata/pgroot/data': Operation not permitted
...
chown: changing ownership of '/home/postgres/pgdata/pgroot': Operation not permitted

I can use the NFS with other postgresql solutions, e.g. with bitnami's helm chart. How could I debug this?
I'm using this NFS provisioner without any custom settings (except for setting NFS server IP and path): https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner

Start by reproducing the failure from the minimal-postgres-manifest.yaml on bare-metal Kubernetes and compare it with the working EKS case. Inspect the nfs-subdir-external-provisioner setup and the reported chown errors; done means identifying the cause and documenting a verified configuration or limitation.