What we are noticing however, are quite a bit of incomplete search strings, incomplete words in the strings etc, characters in strings (commas, hyphens, etc), almost like Google Suggest is a bigger factor in todays' results.
Adding a PS to this up front, I'm noticing that if I use Google Suggest to check out the spelling of a word today, it's showing different ways of typing combinations of syllables to sound it out. I've never seen that before. It's likely that many people are accidentally clicking on the variants.
Thinking out loud, and stretching things a bit... could this possibly be related to testing reported in this thread?
The 404 testing goes back a few months, not just today, and the discussion in the thread is for nonsense in 404s, not search strings... but possibly Google is looking at ways to filter out spurious signals of all kinds, so it needs to deliver them in order to see how much they are ignored (if that logic makes sense).