I do not think you are missing anything: you have identified a flawed interface. Indeed, I can reproduce the inconsistent behavior you indicate. It is not possible to launch a download from within these search results.
On as second try: no. After searching and clicking an item in the search results, the item is “selected”, and may be displayed at the bottom of the list. I have the impression that, occasionally, that selected item is not in the viewport, but today, I cannot reproduce it.
For me currently, this is Boxes 48 in a default Fedora install.