Repository variable Date is not displaying as defined format

User_8DRI6

Created a repository variable as below in OBIEE.

select to_timestamp(to_char(max(run_date) - 4/24 ,'DD/MON/YYYY HH:MI:SS AM'), 'DD/MON/YY HH:MI:SS AM') from XYZ where ABC_STATUS = 'SUCCESS'

When i test the variable in RPD with a defined connection pool or when i display the variable as column in report, the date format is displaying as '4/8/2021 1:04:55 AM'. Is there a way to find the cause of this behavior. Am using other logic on top of this, so i need to display variable date as 'DD/MON/YYYY HH:MI:SS AM'. Database NLS_DATE FORMAT is DD-MON-RR and NLS_TIMESTAMP_FORMAT is DD-MON-RR HH.MI.SSXFF AM

Appreciate your help in advance