What content is it missing.

It has the entire article text and hyperlinks that I can tell.

???

Let's start with the very first paragraph from the original:

  President Trump said last month that talks for a phase 2
  trade agreement with China were on the back burner. If
  they ...

Let's look at the very first paragraph from the "Outline" version:

  I would bring experience, design, engineering and related
  technologies developed over my 40-year career in the
  automotive industry building race cars and ...

Those are clearly different, which means the Outline one is missing content and not fit for purpose.

I didn't bother checking for further differences. There may or may not be any, none of which really matters given the Outline one is incomplete.

Outline tends to attempt to cut out the first portion summary text.

It could be a formatting issue with bitly. Tinyurl may work better in some instances.

Ultimately it does the job tasked, to get you the text locked inside the paywall.

Clearly it's not capturing the entire article text. :(

Personally, I consider that to be a fundamental flaw. eg "Not fit for purpose.