Unable to add mutiple defects in Zyper testcase

[kumar k]

through automation after test fail i am creating defect and adding that defect to Testcase using below API

/rest/zapi/latest/execution/<ExecutioId>/execute

and body as

{
"defectList": [
"${DEFECT_NO}"
],
"updateDefectList": "true"
}

When i reran test again test is failing and creating new defect but in test case it is over writing exiting defect and populating new defect. How can i add 2 defects with out over writing