Wrong query is getting generated in WHERE NOT EXISTS with group by clause

Question

Query is getting generated wrongly in where not exists section when i use group by function.Please prvoide me any clue to over come the problem.
/* DETECTION_STRATEGY = NOT_EXISTS */
INSERT /*+ APPEND */ INTO STG_ETL.I$_DCMT_TIMEZONE_LOOKUP
     TZ_OFFSET,
     ADT_CRT_DT,
     ADT_UPDT_DT,
     IND_UPDATE
SELECT * FROM (
SELECT      
     to_number(KOFAX.RECEIVED_TZ)     TZ_OFFSET,
     min(sysdate)     ADT_CRT_DT,
     min(sysdate)     ADT_UPDT_DT,
     'I' IND_UPDATE
FROM     ESTG.FLAT_FIL_DMS_KOFAX KOFAX
WHERE     (1=1)
And (KOFAX.LD_DT = ( select MAX(LD_DT) from ESTG.FLAT_FIL_DMS_KOFAX INNER
where INNER.ENGAGEMENT=KOFAX.ENGAGEMENT
               and INNER.KOFAX_FILE_NM = KOFAX.KOFAX_FILE_NM
               AND INNER.IM_CUST_ID = KOFAX.IM_CUST_ID
          and INNER.BATCH_ID=KOFAX.BATCH_ID)
AND
(TO_DATE(KOFAX.LD_DT)>=TO_DATE(SUBSTR('#WAREHOUSE.P_EDW_LAST_RUN',1,10),'YYYY-MM-DD'))
And (substr(KOFAX.RECEIVED_TZ,1,1) <> '+')
Group By to_number(KOFAX.RECEIVED_TZ)
) S
WHERE NOT EXISTS (
     SELECT     'X'
     FROM     EDW.DCMT_TIMEZONE_LOOKUP T
     WHERE     T.TZ_OFFSET     = S.TZ_OFFSET AND
     )

Answer 1

Easiest fix for you would be to change the detection_strategy on the IKM from NOT_EXISTS to either :
MINUS
-- Try this out, it should work, it will give the same data through the equiverlant steps.
NONE
-- This will load all incoming data into your I$ table, there will be more rows to crunch in the following 'Flag Rows for Update' step, it might give incorrect results potentially - you will have to test it.
So try MINUS first, failing that, see if NONE gives you what you want in your target.
Are you inserting only new data or updating existing data?