PV/PVC not persistent across system and application restart?

[khteh]

I have a PostgreSQL single-replica application running on my local microk8s. It has the following PVC:

          volumeMounts:
            - name: postgresql-persistent-storage
              mountPath: /var/lib/postgresql
              subPath: postgresql
  volumeClaimTemplates:
    - metadata:
        name: postgresql-persistent-storage
      spec:
        accessModes: ["ReadWriteOnce"]
        resources:
          requests:
            storage: 10Gi

PVC:

postgresql-persistent-storage-postgresql-0   Bound    pvc-373b6765-599e-4177-ae76-097b56911dbd   10Gi       RWO            microk8s-hostpath   35d

PV:

pvc-373b6765-599e-4177-ae76-097b56911dbd   10Gi       RWO            Delete           Bound    default/postgresql-persistent-storage-postgresql-0   microk8s-hostpath            36d

I find out that everytime when my laptop reboots and the application restarts automatically, the tables are empty that I have to reload the data. This contradicts with my understanding that the PV/PVC which has physical SSD storage is persistent storage and shouldn't be cleared by system / application restart unless intentionally done so by the application itself? What do I miss?