Steps to reproduce:

After upgrading Zabbix Agent 2 to 5.0.22 (5.0.22-1.el7)

item.key: pgsql.custom.query["\{$PG.SESSIONNAME}",,,,"postgresql_db_size",,,,,,"postgres"]

preprocess:

script:
postgresql_db_size.sql
##content
SELECT pg_database_size(datname::text) FROM pg_catalog.pg_database WHERE datistemplate = false AND datname = $1;

##

Item is active agent item.

NB! if item is passive agent item, then there is no problems.

Result:
2022/04/05 15:51:36.001584 [Postgres] Cannot fetch data: expected 1 arguments, got 6.
2022/04/05 15:51:36.001624 check 'pgsql.custom.query["POSTGRESQL",,,,"postgresql_db_size",,,,,,"postgres"]' is not supported: Cannot fetch data: expected 1 arguments, got 6.
2022/04/05 15:51:37.001176 [Postgres] Cannot fetch data: expected 1 arguments, got 6.

Expected:
Get value in as expected.