Since May, there have been complaints in the Google Web Search Help forum about Google News not sticking with the search query you entered after clicking on the "all x articles" link on a search result.
You can replicate this yourself by following these steps:
1. Go to Google News 2. Search for anything 3. Find "aggregated" item and click on "all x articles"
You will then notice the search box is blank.
Here is a short screencast demonstrating this:
Again, it was reported at Google Web Search Help in May and then reported again at the Google News Help forum.
The first report didn't really specify Google News, so Googlers didn't understand it, nor did I. But this makes sense.
Forum discussion at Google Web Search Help and Google News Help.