After seeing two reports about it, I checked myself with several PR tools, and all sites show N/A.
Is it a PR update? Temporary issue? PR is gone for good? PR is private and no longer visible? I guess only Google knows.
My guess is temporary issue or private PR (meaning only Google can see it). Google won't give up its huge PR database, which is the foundation of their algorithm (whether they admit it or not).
nadavs