RSS feed showing excerpt when set to full article

I’ve found multiple threads here with the same problem, but not one of them had a solution.

Under the “Reading” tab, I have set RSS feeds to include the full text of the articles, but I am only getting excerpts in Google Reader.

I did find a clue, however. I have several other WP installations, all at 3.2.1, and the XML is different for their feeds than what I’m seeing on the WP installation with the problem.

The only difference is that the WP with the problem is one that was upgraded. But it appears all of the files were freshened when WP was upgraded (it was a year or two old). One of my other blogs is older than that, but has had regular upgrades; another is a newer installation. Both of these work correctly. If you pull up the feed in a browser, and then choose ‘view source,’ you can see what is being delivered by WP. Check out what I found. For both of these you can visit the feed in a browser and choose “view source” to see what is being sent (I’m using Chrome BTW).

Here is the header from one of the WP feeds that work correctly (and they are identical in the feeds that are working). This one is at http://www.recordstoreguide.com/blog/feed :

<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:wfw="http://wellformedweb.org/CommentAPI/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:atom="http://www.w3.org/2005/Atom"
	xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
	xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
	>

…and here is the faulty one, where you can see it is somehow grabbing older RSS spec. This one is at http://exacq.cantonwebservices.com/blog/feed :

<?xml version="1.0" encoding="UTF-8"?><feed
  xmlns="http://www.w3.org/2005/Atom"
  xmlns:thr="http://purl.org/syndication/thread/1.0"
  xml:lang="en"
  xml:base="http://exacq.cantonwebservices.com/blog/wp-atom.php"
   >

I am thinking that possibly two things are happening: either the RSS feed is getting directed to an outdated file (not too likely), or a configuration value in the database might be “sticky” or corrupted, to where I can’t change it. The client is reporting that the blog did deliver a full RSS feed before I upgraded everything. I have tried changing the setting back and forth to show full or partial feeds, but that did nothing. I even tried a plugin that forces a default to the Atom feed, but that did nothing either.

Any thoughts? I’ve spent a couple of hours trying everything I could throw at it… :sigh: