System.InvalidCastException - class & handler without CheckPermission attribute

[mmnosek]

I've got following json:

{
  "Html": "",
  "SomeNotSecuredProperty": {
    "SomeProperty": 0 
  } 
}

and json-behind:

 [RequirePermission(typeof(ViewSpecificThing))]
    public partial class ExampleChildrenDataPage : Json, IBound<Thing>
    {
        [ExampleChildrenDataPage_json.SomeNotSecuredProperty]
        public partial class PropertyItem : Json
        {
            private void Handle(Input.SomeProperty action)
            {
                //some code
            }
        }
    }

And when I trigger SomeProperty change, exception is thrown:

System.InvalidCastException : Unable to cast object of type 'PropertyItem' to type 'Starcounter.Authorization.Tests.PageSecurity.ExampleChildrenDataPage'.
   at lambda_method(Closure , Json , Input`1 )
   at Starcounter.Templates.Property`1.InvokeHandler(Json parent, Input`1 input) in C:\TeamCity\TeamCity10\buildAgent\work\sc-pnext-nightly-334\Level1\src\Starcounter.XSON\Templates\Foundation\Property.cs:line 262
   at Starcounter.Templates.Property`1.ProcessInput(Json parent, T value) in C:\TeamCity\TeamCity10\buildAgent\work\sc-pnext-nightly-334\Level1\src\Starcounter.XSON\Templates\Foundation\Property.cs:line 284