ORA-01400: cannot insert NULL into ("IFSAPP"."CUSTOMER_INFO_ADDRESS_CFT"."ROWKEY")

Hi,

I get the following oracle error message in ‘Customer Invoices with errors’ window since 3rd May. ”ORA-01400: cannot insert NULL into ("IFSAPP"."CUSTOMER_INFO_ADDRESS_CFT"."ROWKEY")”

I have added a new custom field to CustomerOrder LU on the same day. 

Only CUSTCOLDEB (debit collective invoices) shoots out this error.

Code in new CF

SELECT 'Företag - Återstående limit' || CHR(13) || CHR(10) || cl.comp_limits AS "Företag och återstående limit"
FROM (SELECT LISTAGG(COMPANY || ' - ' || 
              CASE WHEN CREDIT_BLOCK = 'TRUE' THEN 'STOPPAD'
                   ELSE TO_CHAR(ROUND(NVL((SELECT remain_credit1
                                             FROM IFSAPP.customer_credit_collection_qry q
                                            WHERE q.identity = c.identity
                                              AND q.company = c.company), CREDIT_LIMIT)), 'FM999G999G999')
              END, CHR(13) || CHR(10)) WITHIN GROUP (ORDER BY COMPANY) comp_limits
FROM IFSAPP.CUSTOMER_CREDIT_INFO_CUST c
WHERE IDENTITY =  :customer_no) cl
WHERE :objstate IN ('Planned', 'Released', 'Blocked')
AND NOT EXISTS (SELECT 1 FROM IFSAPP.company_site
WHERE contract = :customer_no)

In CUSTOMER_INFO_ADDRESS_TAB, Rowkey is set to Nullable FALSE and default value is set to sys_guid().

Any idea why this error message occurs?
Appreciate your time.

Version - IFS Apps10 UPD16