My theory:
Google rolled out Panda update only to the English Search, but today they announced that they will roll out the Panda update for every other language as well:
http://googlewebmastercentral.blogspot.com/2011/08/high-quality-sites-algorithm-launched.html
I think that the PR of the affected sites will change because of their new way of valuing websites.
Good luck to all of you with your PR!
Edit: Also the English websites won't notice a pr change cause that happened the last time they updated pr so fast, now it's time for the rest of the world, just a theory though.