Jenkins cucumber reports plugin buildStaus has no affect

I coudn't get the build status change to UNSTABLE in jenkins. seems cucumber buildStatus has no affect ? or it would be helpful to know what i am doing wrong ?

post {
    always {
        cucumber buildStatus: 'UNSTABLE',
                failedFeaturesNumber: 1,
                failedScenariosNumber: 1,
                skippedStepsNumber: 1,
                failedStepsNumber: 1,
                fileIncludePattern: '**/*cucumber-report.json',
                trendsLimit: 10
    }

}