Am I correct, Sgt_Kickaxe, that these aren't meta keywords... more likely on page keywords that one occasionally sees on publicly published or intranet articles, sometimes on reference sites? Also, are these articles from a common source? I sometimes put keywords in text files on my computer to help me find them later.
I'm guessing that this is a title renaming glitch, perhaps even a publishing glitch followed by a title renaming glitch. My guess is that Google ranked the article(s), didn't like the title(s), searched the page itself, and found a keyword list high up on the page which fit the query, and grabbed it. It may even be that the keyword lists weren't intended for publication, but somehow ended up there.
I wouldn't assume that this is a trend.