Google Panda 4.1 Weekend Refresh?

A couple weeks ago, Google pushed out a large update to the Google Panda Algorithm, version Panda 4.1.

A weekend later, we saw major traffic shifts in Google, which Google said was likely Panda 4.1 still in the process of rolling out 1.5 weeks later.

But now, almost 2.5 weeks later, we are still seeing Panda swings. Glenn Gabe posted on Twitter that he is seeing "another Panda tremor yesterday (10/12)."

Glenn Gabe, who follows Google Panda sites incredibly closely added:

Adam Melson added:

Glenn also shared a Google Webmaster Tools chart of a Panda client but explained this is data from 10/11 and 10/12 should be way higher:

San Sharp shared a chart from SearchMetrics of a Panda 4.1 winner:

There is some chatter at the generic WebmasterWorld thread:

...and reversed again.

Is it just me, or is anyone else here seeing this yo-yo effect?

My guess is that something is being tested that affects "a small minority of sites", and is probably small enough and subtle enough to get under the radar of most observers: I only notice because it is my site, and I have only noticed the other couple of sites affected in my sector because, as a result of what my site is doing, I have taken a more detailed look at what is happening there.

I also had the rare opportunity, last week, off using a brand-new laptop on a new wi-fi network near (but not in the same immediate area as) my own system. The results - very obviously tightly focused on location - were interestingly different from what I have seen elsewhere locally, and really do confirm that there is now no such thing in Google as a "neutral" set of results.