Hello,
I've simulated your case
- schema was created via .hdbschema
- table in that schema was created with SQLEditor under SYSTEM user
- a procedure was created via .hdbprocedure
- SYSTEM user was granted EXECUTE privelege on that schema call "_SYS_REPO"."GRANT_SCHEMA_PRIVILEGE_ON_ACTIVATED_CONTENT"('execute','<schema name>','SYSTEM');
- a procedure was called from SQLEditor call "<schema name>"."tst.data::test";
- result set was ok. no errors.