This is a really strange behaviour and I hope I'm not doing anything silly here. I have this code:

public class BlogSurfaceController : SurfaceController
{
    [ChildActionOnly]
    public PartialViewResult ExploreMore(int size = 4)
    {
        var articles = Umbraco.ContentAtXPath("//" + Post.ModelTypeAlias);                  

        return PartialView("Blog/_RandomArticles", articles);
    }
}

Super simple. If I hover with the mouse over where the articles are retieved I get 4 articles. Then I hover over the articles variable in the return statement and I get an empty value then I hover over the previos=us articles again and it's empty.

I got to this issue trying to get random articles from my blog, when I iterate over the collection the script can't find any articles, but they were there!