milosevic - 5:31 am on Jul 3, 2011 (gmt 0)
I've just witnessed this exact issue while trying to find a link to some content on a site where it's link from the main page had broken. I found a page with an old non-friendly URL link which turned out to still work. However, using the cached search to find the highlighted text I wanted quickly was very strange.
These terms only appear in links pointing to this page: search hl en&biw 1920&bih 1036&q
This is on a (general interest, non-commercial) site which has been completely inactive for a couple of years. Note I was searching for a three word "name of article", which weren't referenced on the cached page I looked at all. I did find them on the page as shown in the SERP with f3. Seems like some sort of gremlins at Google's end to me