Why does this continue to INSERT when it should merely UPDATE?

INSERT into tasks_master_tracker_idb (
CLIENT_CONTACT, COMPLEXITY, CREATED_BY, CUSTID, DIRECTION,
INTEGRATION_ID, INTEGRATION_NAME, INTEGRATION_STATUS, INTEGRATION_TYPE, VENDOR
)
   SELECT t.CLIENT_CONTACT, t.COMPLEXITY, t.CREATED_BY, t.CUSTID, t.DIRECTION,
   t.INTID, t.NAME, t.STATUS, t.PROJ_TYPE, t.VENDOR 
   FROM
   tasks t
   WHERE 
   t.CUSTID='DPR01'
   AND
   t.INTID='INT0001'
ON DUPLICATE KEY UPDATE
CLIENT_CONTACT = (SELECT t.CLIENT_CONTACT FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
COMPLEXITY = (SELECT t.COMPLEXITY FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
CREATED_BY = (SELECT t.CREATED_BY FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
CUSTID = (SELECT t.CUSTID FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
DIRECTION = (SELECT t.DIRECTION FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
INTEGRATION_ID = (SELECT t.INTID FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
INTEGRATION_NAME = (SELECT t.NAME FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
INTEGRATION_STATUS = (SELECT t.STATUS FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
INTEGRATION_TYPE = (SELECT t.PROJ_TYPE FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001'),
VENDOR = (SELECT t.VENDOR FROM tasks t WHERE t.CUSTID='DPR01' AND t.INTID='INT0001')