Did you find the root cause of this issue? We are seeing the same exact behavior on few servers ( Win 2008 R2, QL 2008 R2). PLE spikes to millions of seconds in a very short time . It coincides with the Monthly Windows patches and restarts. I expect the PLE to drop when the server restarted , but it spikes to millions of seconds.

I have opened a MS connect incident and see if it gets any traction?

MS Connect Item: