Do this as the supervisor_user since the services user won't be able to write to the cfg dir.

playbooks/roles/supervisor/templates/pre_supervisor.conf.j2

@@ -3,5 +3,5 @@ description     "Tasks before supervisord"
 start on runlevel [2345]
 task
 
-setuid {{ supervisor_service_user }}
+setuid {{ supervisor_user }}
 exec {{ supervisor_venv_dir }}/bin/python {{ supervisor_app_dir }}/pre_supervisor_checks.py --available={{supervisor_available_dir}} --enabled={{supervisor_cfg_dir}}