Angular checkboxes disapear on select

I have a list of checkboxes in my app:

<div class="col-md-6" ng-repeat="item in segment.items">
    <div class="checkbox">
        <label>
            <input 
              type="checkbox" 
              ng-model="item" 
              ng-checked="item.enabled" 
              value="{{item.id}}" 
              class="segment-visibility-checkbox" 
            />
               {{item.name}} <code>/ {{item.slug}}</code>
        </label>
    </div>
</div>

The data, that exists on the $scope as segment.items, looks something like this:

[
    {"id":1,"slug":"nl","name":"Dutch","enabled":true},
    {"id":4,"slug":"en","name":"English","enabled":false},   
    {"id":2,"slug":"fr","name":"French","enabled":true},    
    {"id":3,"slug":"de","name":"German","enabled":false}
]

This renders fine on load, and the correct checboxes are checked. However, if I select a checkbox, the label disappears and the binding appears to be lost. If I deselect a checkbox, it seems to work fine, but if I select it again, it disappears as well. No errors show up in the console.

This is what it looks like on load:

And as soon as I click on "English" I get this

I'm new to Angular so I suspect I am doing something obvious wrong. Can anybody please point me in the right direction?