“We think you are creative to do that.”
You thought right.
That solution is elementary. It amounts to manually attaching an image to a post, which is not a favoured method of using WordPress. I’m expecting you to disagree, but it won’t change the facts of what is observed.
The reality is that a method of
1. extracting an image in a post, and
2. making that image a featured image, without it appearing duplicated –
ought to be scripted, or a script generate to achieve what I and others will come to need.
In the current configuration, it seems to mean that anyone using these features cannot expect the first image (or be able to select one of many in a post) to be featured without a duplicate being seen on viewing the actual post, unless that image is added separately and manually as a featured image. I don’t know why all that is something you would want as developers.
I would have thought an efficient method of achieveing what I’m looking for would be better for your NewsPress theme, and for your business. It’s either it can be done or it’s impossible. I hope it’s not the latter.