Invalid data directory permissions after pod rescheduling

Environment:
kubernetes 1.17.4
rook-ceph as persistent storage provider
postgres-operator 1.4.0 installed with helm chart
posgresql resource declared as follows:

kind: postgresql
metadata:
  name: test-postgres
  namespace: test
spec:
  teamId: test
  volume:
    size: 50Gi
    storageClass: rook-ceph-block
  numberOfInstances: 2
  users:
    zalando:
    - superuser
    - createdb
    service: []
  databases:
    db_1: service
    db_2: service
  postgresql:
    version: "12"
    parameters:
      max_connections: "500"

Problem:
After pod with postgresql instance had been rescheduled to another node postgresql server doesn't start with following error:

2020-05-09 14:07:17 UTC [2507]: [2-1] 5eb6b915.9cb 0     DETAIL:  Permissions should be u=rwx (0700) or u=rwx,g=rx (0750).                                                                      
2020-05-09 14:07:17,085 INFO: postmaster pid=2507                                                                                                                                               
/var/run/postgresql:5432 - no response                                                                                                                                                          
2020-05-09 14:07:17,116 WARNING: Postgresql is not running```
/home/postgres/pgdata/pgroot/data - have following permissions:
```# ls -alh pgdata/pgroot
total 16K
drwxrwsr-x  4 postgres postgres 4.0K Apr 29 11:34 .
drwxrwsrwx  4 root         1337 4.0K Apr 29 11:33 ..
drwxrws--- 19 postgres postgres 4.0K May  9 14:05 data
drwxrwsr-x  2 postgres postgres 4.0K May  5 20:49 pg_lo```

Workaround:  change permissions to 750 by hands

Start by reproducing the pod rescheduling scenario with the listed Kubernetes, rook-ceph, postgres-operator, and PostgreSQL versions, then trace how the data directory permissions are set and preserved across nodes. Done means a rescheduled PostgreSQL pod starts without manually changing permissions and the relevant regression is covered by the project's available tests.