PostgreSQL 12 error unrecognized configuration parameter zbx_tmp.wal_json_res

Hi all,

We are currently running Zabbix 5.0 with PostgreSQL 12, and history and
trend data partitioning.
History and trend data housekeeping has been disabled in Zabbix.

In the PostgreSQL logs, we get the following error:

2023-12-06 09:12:47 CET [3509536-5] zabbix(at)postgres STATEMENT: select
current_setting('zbx_tmp.wal_json_res');
2023-12-06 09:17:47 CET [3516312-1] zabbix(at)postgres ERROR: permission
denied for function pg_ls_waldir
2023-12-06 09:17:47 CET [3516312-2] zabbix(at)postgres CONTEXT: SQL statement
"SELECT row_to_json(T) FROM (
SELECT pg_wal_lsn_diff(pg_current_wal_lsn(),'0/00000000') AS WRITE,
count(*) FROM pg_ls_waldir() AS COUNT
) T"
PL/pgSQL function inline_code_block line 10 at SQL statement
2023-12-06 09:17:47 CET [3516312-3] zabbix(at)postgres STATEMENT: DO LANGUAGE
plpgsql $$
DECLARE
ver integer;
res text := '{"write":0,"count":0}';
BEGIN
SELECT current_setting('server_version_num') INTO ver;

IF (SELECT NOT pg_is_in_recovery()) THEN
IF (ver >= 100000) THEN
SELECT row_to_json(T) INTO res FROM (
SELECT pg_wal_lsn_diff(pg_current_wal_lsn(),'0/00000000') AS WRITE,
count(*) FROM pg_ls_waldir() AS COUNT
) T;

ELSE
SELECT row_to_json(T) INTO res FROM (
SELECT pg_xlog_location_diff(pg_current_xlog_location(),' 0/00000000') AS
WRITE,
count(*) FROM pg_ls_dir('pg_xlog') AS COUNT
) T;
END IF;
END IF;

perform set_config('zbx_tmp.wal_json_res', res, false);
END $$;
2023-12-06 09:17:47 CET [3516312-4] zabbix(at)postgres ERROR: unrecognized
configuration parameter "zbx_tmp.wal_json_res"
2023-12-06 09:17:47 CET [3516312-5] zabbix(at)postgres STATEMENT: select
current_setting('zbx_tmp.wal_json_res');

This seems to be related to permissions-problem and missing/unknown
configuration parameter.
We found the following article describing how to set correct permission:

https://github.com/bitnami/charts/issues/20247

Is this a known issue? Should we just perform the step according to
procedure in above link to set permission, or will security be degraded as
commented in article?

Please advise.

Best regards,
Arne H.