@bipinchandra92 - Can you verify that, When you are hitting short URL then are you getting :children property in en.model.json ?
This happens when you page data is loaded from home.model.json instead of en.model.json.
So, In first case your data gets fetched from root e.model.json and whereas in second case it gets fetched from home.model.json(respecctive page).
As per my understanding you :path property in preview mode of en.model.json should match with the request URI. So when you hit short path i.e without /content/project-name it looks for :path property in en.model.json where it doesn't match and moves to individual page's model.json i.e home.model.json