XrayImportBuilder adding new test cases to Test Execution instead of updating the existing test cases

Question

We are using XrayImportBuilder to Import test results TestNg from our Jenkins job to Jira for the Automation . The parameters are defined in the Jenkins File as below

stage('Import results to Xray') {
    steps {
        step([$class: 'XrayImportBuilder', 
               endpointName: '/testng', 
               importFilePath: 'target/surefire-reports/testng-results.xml',     
                importToSameExecution: 'true', 
                serverInstance: 'ecc67055-c359-40cb-8b8a-a44cb9f6ca30'
                 testExecKey: 'CPT-123'])
    }
}

Until last week, the Jenkins jobs which ran 2 times a week, updated the Existing Test Cases in the Test Execution - CPT-123 with the results - PASS/FAIL. However when the last Jenkins build that ran on Monday morning , new test cases were created , instead of the existing test cases being updated. This is causing duplicate test cases being created. No changed have been made in the Automation code , nothing new was pushed since last 3 months .

Any inputs highly appreciated

I was expecting that the existing test cases be updated in the test execution - CPT-123 , but instead it created additional test cases and added to the Test execution