HELP!!-ORA-01830: date format picture ends before converting entire input string- 12c. DB 12.2.1.30

Hello

I am facing a strange PLSQL Problem. This is on 12c. DB 12.2.1.30

Details below:

1. Following procedure is run from SQL.

set serveroutput on
DECLARE
outf VARCHAR2(2000);
begin
TYPE2_DATA_UPDATES.type2_lease_selections_prc (
    request_id_p => 1234,   
    from_date_p => '01-DEC-2026',   
    to_date_p  => '31-DEC-2026',   
    last_run_by_p => 'SPIPROD',
    letter_name_p => 'Type II - Expiration Memo',   
    run_check_p =>  'T', 
    char_code_p =>   '230',
    status_f   =>  outf
  );
   
  dbms_output.put_line(outf);
   
end;

2. When run, it gives following error:

-ORA-01830: date format picture ends before converting entire input string

ORA-06512: at "SPIPROD.TYPE2_DATA_UPDATES", line 853