STEPS TO REPRODUCE:

1. Go to PlatformUI;
2. Create an article "Article 1"
3. Create a content type that has a "Object Relation" fieldtype
4. Create an object of previous created content type, and define a relation with "Article 1"
4. Preview the article. Here we can see that the "Article 1" do not appear as being related with the created object

If we do the same steps, but using an "Object Relation*s*", then the related object(s) is shown.