Google has confirmed they have pushed out a Panda refresh this past Monday.
This updated affected less than 1% of search queries and is a “minor” Panda refresh. We emailed Google, after hearing speculation of a Panda update and Google confirmed it by tweeting it.
Here is that tweet:
Panda data refresh this past Monday. ~1% of queries noticeably affected. More context: goo.gl/wQRZ0
— A Googler (@google) August 22, 2012
The previous Panda update was version 3.9 on July 24th, so just about a month ago.
I know at least one Panda “victim” who recovered this past Monday due to this refresh.