Angularjs ng型号选项="；{时区：utc'；utc'；}”；在启动盒确认模式打开时重置ng模型值

我正在使用

ng model options=“{timezone:'utc'}”

以utc格式显示我的日期。但在同一屏幕上，我有一个按钮，打开引导框模式，当它打开时，ng模型被清除。这很奇怪，因为该函数中没有提到日期。下面是代码。提前感谢

<input ng-model-options="{timezone: 'utc'}"
                                    type="text"  name="creationDate" class="form-control req" uib-datepicker-popup="{{format}}" is-open="popup2.open" datepicker-options="dateOptions1" placeholder="{{vm.user.creationDate | date:'dd/MM/yyyy' : 'UTC'}}"  ng-model="vm.user.creationDate" ng-init="vm.user.creationDate  = vm.user1.creationDate" ng-change="vm.maturity(vm.user.creationDate, 'creationDate')" close-text="Close" alt-input-formats="altInputFormats" readonly="readonly" required />

bootbox.confirm("Are you sure want to delete Test?", function (result) {
    console.log(vm.user);
    if (result == false) {
    return;
    } else {
    let data = Object.assign({}, vm.user);
    data.exposureId = vm.user1._id;
    data.amount = (data.amount + "").split(',').join('');
    UserService.DeleteTest(data).then(response => {
        console.log(response);
        vm.message = response.message;
        vm.show = true;
        $scope.isChecked = false;
        $timeout(function () {
            $scope.isChecked = true;
        }, 4000);
    });
    }
});