Why am I getting error 17410 end of data on my rest api when I add a parameter to the query - rest

Question

I have ORDS 21 installed in a local 19c oracle database. I have created a stored procedure to list all the departments from the dept table with a cursor that lists the employees from the emp table. If I just list all departments and their employees the api works fine, but if I add a parameter to the query to specify which department, I get an error 17410 no data left .
Both queries are backed by plsql stored procedures. I have created many stored procedures using this same format with parameters and nested cursors before without a problem.
MWE for query that works:
create or replace procedure get_dept
as
l_cur sys_refcursor;
begin
open l_cur for
select d.deptno,d.dname,
cursor (select e.empno,e.ename
from emp e
where e.deptno = d.deptno
order by e.deptno,e.empno
) as employees
from dept d
order by d.deptno;
-- return the resultset in json format
apex_json.open_object;
apex_json.write('emps',l_cur);
apex_json.close_object;
end get_dept;
/
MWE for query that does not work:
create or replace procedure get_dept1
(
p_dept_no in varchar2
) as
l_cur sys_refcursor;
begin
open l_cur for
select d.deptno,d.dname,
cursor (select e.empno,e.ename
from emp e
where e.deptno = d.deptno
order by e.deptno,e.empno
) as employees
from dept d
where d.deptno = to_number(p_dept_no)
order by d.deptno;
-- return the resultset in json format
apex_json.open_object;
apex_json.write('emps',l_cur);
apex_json.close_object;
end get_dept1;
/