Merging Sell Shipment Error

Summary:

Error while merging sell shipment

Content (please ensure you mask any confidential information):

I use DUS to insert line in the shipment_cost upon a custom agent event when attribute_number4 in sell shipment is modified
INSERT INTO SHIPMENT_COST (
SHIPMENT_COST_SEQNO,
SHIPMENT_GID,
ADJUSTMENT_REASON_GID,
ATTRIBUTE1,
COST_TYPE,
COST,
COST_GID,

BILLABLE_INDICATOR_GID,
IS_COST_FIXED,
EXCHANGE_RATE_GID,
DOMAIN_NAME
)
SELECT
(SELECT NVL(MAX(SHIPMENT_COST_SEQNO),0)+1 FROM SHIPMENT_COST) AS SHIPMENT_COST_SEQNO,
S.SHIPMENT_GID,
'CREW.CUSTOMER SERVICE ADJUSTMENT',
(SELECT ORDER_RELEASE_GID FROM ORDER_MOVEMENT WHERE SHIPMENT_GID = S.SHIPMENT_GID),