Using the modules Rules and Facebook Autopost, the previous post body summary is used instead of the current post
Your publish_to_facebook is NOT your very last Rules action. In fact, as per the save_entity which follows it, it appears that you are publishing to Facebook something that hasn't been saved yet. So that at least seems to explain what you see happening.

Any attempt to get it to work should ensure that you only publish something that has been saved. So you may want to try by just swapping the last 2 rules actions.

The above is just a quick and dirty attempt, and I doubt you'll actually get it to work like that. But your question reminds me about issue # 430274, and somehow explains that "after saving something" actually happens "before saving something". This is not a bug, but simply how the Rules module works.

A possible compromise to avoid these kind of issues, is to move your  publish_to_facebook action into a second Rules or component in order to ensure that the node is definitely saved correctly.


Method 1: Your original Rule "schedules the execution" (using the
Rules Scheduler sub-module) of that Rules component. For example
after only a few seconds or minutes if your cron job runs frequent
enough (otherwise it'll be next time cron runs). This compromise will
ensure that, at the time the Rules component is executed, the entity
is for sure saved (so that can't be the reason anymore then why
things don't work as expected).
Method 2: Add a Boolean field to the node type and when using Rules
to create the node, set it to "off". Then add a redirect to the
created node as the last action.
After that, create a second rule for "Content is viewed" which will make the Facebook post.
Condition: "Boolean field == Off".
Action 1: Post to Facebook using viewed node's data.
Action 2: Set a Data Value: Boolean field == "On".


If none of the above helps, maybe it's worth to do some Rules debugging, as detailed in "How can I display the value of a variable inside a condition?".

Note: In 1 of your (moved to chat) comments, you also added this:


  Facebook returns a unique identifier that must be saved as part of the entity so I can further code updates or deletes if necessary. 


If I was to make this work, I would first make the original question work, which is about "add a new article" (updates or deletes is an additional challenge). Because as long as you've not succeeded in that, there is nothing to update or delete ...