Sorry but could not reproduce the problem 
with the following products:
PB 12.5.2 build 5652
ASE client 15.7 EBF22688
ASE server 15.7 EBF 19496
Tested with ASE and SYC database profiles
// Profile ASE
SQLCA.DBMS = "ASE Adaptive Server Enterprise"
SQLCA.Database = "repro"
SQLCA.LogPass = <**********>
SQLCA.ServerName = ""
SQLCA.LogId = "sa"
SQLCA.AutoCommit = False
SQLCA.DBParm = ""
// Profile SYC
SQLCA.DBMS = "SYC Adaptive Server Enterprise"
SQLCA.Database = "repro"
SQLCA.LogPass = <**********>
SQLCA.ServerName = "xxxxxxxx"
SQLCA.LogId = "sa"
SQLCA.AutoCommit = False
SQLCA.DBParm = "Release='15'"
Below is the source of my stored procedure.
Prior to run the script, execute a data pipeline to create ASA tables (EAS Demo DB V12.5) department and employees into your ASE server
CREATE PROCEDURE mySP
AS
BEGIN
create table #employee_working (
emp_id int not null,
manager_id int null,
emp_fname varchar(20) not null,
emp_lname varchar(20) not null,
dept_id int not null,
dept_name varchar(40) not null )
insert into #employee_working
select employee.emp_id, employee.manager_id, employee.emp_fname, employee.emp_lname, employee.dept_id, department.dept_name
from employee , department
where employee.dept_id = department.dept_id
select #employee_working.emp_id, #employee_working.manager_id, #employee_working.emp_fname, #employee_working.emp_lname,
#employee_working.dept_id, #employee_working.dept_name
from #employee_working
END
Jacob