I have promoted the use of Reader View in Safari (I’m at version 12.1) for viewing web pages without the intrusion of advertisements. I even, for some web sites, set Safari Preferences so the site comes up in Reader view and I don’t have to use Command Shift R to invoke it.
However I have discovered that Reader View does not present some web pages with the full text. It often starts at the 2nd or later paragraph
For example, here are two screen shots from the Wall Street Journal
The first is before Reader View is activated. Note that the 3rd paragraph begins with “But many . .”
Here is the Reader View of that web page. The 1st two paragraphs are missing
I don’t know if this is a recent “improvement” but now do NOT automatically use Reader View