Weird input name generated by CheckBoxFor - asp.net-mvc

Question

The issue is that for some bizarre reason, when I use CheckBoxFor I get a checkbox but the ID has "CS___8__locals1" in it. No idea where this comes from or why it's happening.
Any ideas? See below:
<input class="checkbox" id="ProductPlans_0__CS___8__locals1_plans_4__IsSelected" name="ProductPlans[0].CS$<>8__locals1.plans[4].IsSelected" type="checkbox" value="true" />
My model is a single object (it is in reality part of a collection of objects but that should not matter. Here is my editor template (leaving out the #model declaration):
<tr>
<td>
<label class="checkbox">
#Html.CheckBoxFor(x => Model.IsSelected, new { #class = "checkbox" })
<strong>#Model.MarketingLabel</strong>
#Html.Raw(#Model.DisplayName)
</label>
</td>
<td>
<span data-planid="#Model.Id">#Model.Premium.ToString("C")</span>
</td>
<td>
Explain
</td>
#Html.HiddenFor(x => Model.Id)
</tr>

Answer 1

I know this is and old post but maybe will help someone else out there.
So, in my case I had this same problem and the problem was solved after a few try and error and we discover that the error was in itself the for loop.
Our model was something like this:
for (int i = 0; i < PatiosCobro.Count; i++)
{
<div class="col-md-4 col-sm-4 col-xs-12">
<div class="input-group input-group">
<div class="form-line">
#Html.TextBoxFor(model => PatiosCobro[i].Valor, new { htmlAttributes = new { #class = "form-control" } })
</div>
#Html.HiddenFor(model => PatiosCobro[i].CobroId)
#Html.NameFor(model => PatiosCobro[i].Valor)
</div>
</div>
}
This will throw "CS___8__locals1_ETC"
What worked for us was taking out the local variable i and declaring it out in other place.
by example:
int i = 0;
for (i = 0; i < PatiosCobro.Count; i++)
{
<div class="col-md-4 col-sm-4 col-xs-12">
<div class="input-group input-group">
<div class="form-line">
#Html.TextBoxFor(model => PatiosCobro[i].Valor, new { htmlAttributes = new { #class = "form-control" } })
</div>
#Html.HiddenFor(model => PatiosCobro[i].CobroId)
#Html.NameFor(model => PatiosCobro[i].Valor)
</div>
</div>
}