Checkbox not functioning well on iPhone4 portrait (Responsive)

Using iPhone 4 and 5 only on portrait, when I click the checkbox, the tick shows for half a second and disappears in the middle of the line (not even on the box). The model changes, but the checkbox stays as it was when we entered portrait (if you change to landscape it will show the right state and when going back to portrait it stops working again).

It works fine on landscape or larger screens.

HTML:

<div class="col-md-12 col-xs-12">
<input type="checkbox" name="testcheckbox" id="testcheckbox" ng-model="myData" />
<label id="spantextcheckbox" for="testcheckbox">Test</label>
</div>

I got a media-query for those devices (separate for landscape and portrait), but the checkbox has no classes, means the query shouldn't work on it. Still, for some reason, the checkbox works fine on larger devices or even landscape of those devices.