Hi!
Unfortunately this is most likely not related to the search plugin at all. Try opening the same result page when the search plugin is inactive, it should be displayed the same way.
What I’m guessing is that the widget manager might be applying some of the content filters, and it results in displaying the content (attachment in your case) once again.
If the problem does go away if the search plugin is inactive, then I gladly take a look. Otherwise it’s probably unfortunately not related.