Certain queries are broken
I concur. We got hit overnight 6/7th September; we've been researching it since then. At some point yesterday, various types of queries started returning rubbish.
Some were irrelevant. Some were extreme domain crowding. I saw one query (for a 301'd domain) come up with two full pages of results for the same review site, reviewing that domain. (It's now back to showing the redirection target domain).
Yesterday:
[BrandedExample.co.uk]
AcmeReviewSite: See reviews for Brand Name
AcmeReviewSite: See reviews for Brand Name
AcmeReviewSite: See reviews for Brand Name
AcmeReviewSite: See reviews for Brand Name
Today:
[BrandedExample.co.uk]
BrandedExample.com/
BrandedExample.com/somepage
BrandedExample.com/anotherpage
BrandedExample.com/yougettheidea
Odd things happening at the moment.