钉钉小程序picker组件选择器的粒度无法控制到日

示例代码：

<view class="cu-form-group">  
                    <view class="title">巡查日期</view>  
                    <picker mode="date" :value="date" start="2015-09-01" end="2060-09-01" @change="DateChange" fields="day">  
                        <view class="picker">  
                            {{date}}  
                        </view>  
                    </picker>  
                </view>

操作步骤：

<view class="cu-form-group">  
                    <view class="title">巡查日期</view>  
                    <picker mode="date" :value="date" start="2015-09-01" end="2060-09-01" @change="DateChange" fields="day">  
                        <view class="picker">  
                            {{date}}  
                        </view>  
                    </picker>  
                </view>

预期结果：

<view class="cu-form-group">  
                    <view class="title">巡查日期</view>  
                    <picker mode="date" :value="date" start="2015-09-01" end="2060-09-01" @change="DateChange" fields="day">  
                        <view class="picker">  
                            {{date}}  
                        </view>  
                    </picker>  
                </view>

实际结果：

<view class="cu-form-group">  
                    <view class="title">巡查日期</view>  
                    <picker mode="date" :value="date" start="2015-09-01" end="2060-09-01" @change="DateChange" fields="day">  
                        <view class="picker">  
                            {{date}}  
                        </view>  
                    </picker>  
                </view>