The Object is being created perfectly, I've checked.
The collection's Add() method is something like:
Since you know you're adding MyObject objects, first of all check for that:
public function Add(MyObject $object)
public function Add($object)
{
$this->arr_objects[intval($object->position)] =
$object; < THIS LINE IS THE PROBLEM
From the code provided, I don't see an $object->position property. Are you sure it is there and it is an integer? If you are only getting two values in your iterator then this expression might be evaluating a TRUE to a 1 and a FALSE to a 0... and would overwrite those indexes on each Add().
$this->count++;
}