Emberjs无法读取未定义的属性

Question

我有以下模板：

    {{#each item in controller.pagedAutomationExceptions}}
    {{log item}}

    <tr {{bindAttr class="item.rowClass"}}>
        <td class="text-center">{{unbound item.BTicket}}</td>
        <td>{{unbound item.Reason}}</td>
        <td>{{unbound item.TimeReceived}}</td>
        <td>
            {{#if item.ShowContactVoltageSources}}
                {{view Ember.Select 
                    contentBinding="controller.contactVoltageSources" 
                    optionValuePath="content.Name" 
                    optionLabelPath="content.Name" 
                    valueBinding="item.AutomationValue" 
                    prompt="Choose one..."}}
            {{/if}}

            {{#if item.ShowVoltageField}}
                {{view Ember.TextField valueBinding="item.AutomationValue"}}
            {{/if}}

            {{#if item.ShowEnergizedObjects}}
                {{view Ember.Select 
                    contentBinding="controller.energizedObjects" 
                    optionValuePath="content.Name" 
                    optionLabelPath="content.Name" 
                    valueBinding="item.AutomationValue" 
                    prompt="Choose one..."}}
            {{/if}}
        </td>
        <td>
            {{#if item.Errored}}

            {{/if}}

            {{#if item.IsUpdating}}
            <btn class="btn btn-primary" disabled="disabled">
                Updating..
            </btn>
            {{else}}
            <btn {{action updateAutomationException item target="controller"}} 
                class="btn btn-primary">
                Update
            </btn>
            {{/if}}
        </td>
    </tr>
    {{/each}}

一切都按预期工作，但当我尝试更改路线时，我收到以下错误：

未捕获的TypeError：无法读取未定义的属性'IsUpdating'

如果我删除该行，那么还有一些其他属性无法读取。我不确定发生了什么，显然ember以某种方式获取未定义的对象，但我不知道如何，我实例化我的每一个对象并将它们推送到数组上。

这是控制器（对不起，如果它不准确，我离开工作，所以我从记忆中做到这一点，我也改变了大约一百万次尝试解决问题，这就是为什么我不认为问题是在那里）：

App.Exception = Ember.Object.extend({
    // properties used in template, etc..
});

App.ExceptionsController = Ember.Controller.extend({
    init: function () {
        this._super();

        // ajax request to get exceptions from database
        // once inspections are loaded
        // set(automationExceptions, response)
        // loadMoreExceptions()
    },

    automationExceptions: [],

    pagedAutomationExceptions: Ember.A(),

    loadMoreExceptions: function () {

        // i have a variable that i store to tell me 
        // how many exceptions I'm currently showing.
        // If there are more, I just add to this variable
        // the paging amount, and for those elements 
        // create a new exception and add it to the 
        // paged array. This method also seems to work
        // because I get more records on the view.
        for (; currentTake < newTake; ++currentTake) {
            var simple = automationExceptions[currentTake];
            this.get('pagedAutomationExceptions').pushObject(
                App.Exception.create(simple));
        }

    },

    updateAutomationException: function () {

        // ajax post update, this works fine..

    }
});