Paizo is taking no chances with the 2nd edition of Pathfinder. They worked hard on it in their offices for a while, and now they're giving all of you a chance to give it a going-over. But it's not just a one-and-done. They're updating the rules as you go along, giving your feedback. The first round of changes have been made, and they'd like you to see how they look, as well as a new adventure for you to test out things on.
From the website:
Starting today, you're going to begin seeing some rules updates from the team to clarify or fix issues with the current draft of the playtest. Rather than focusing on typos or other small errors, we're going to try and keep the updates restricted to things that we think are problematic to the gameplay if left as-is. In the coming weeks, you might also see us replace entire subsystems of the game, if warranted by playtest feedback.
The updates themselves are broken into two categories. The first is critical updates. These are issues that distort the game heavily and should be fixed immediately. The second category, just called updates, refers to rules that are important enough to warrant a fix, but that have a relatively limited impact at the game table. There are plenty of other changes we're noting as well, but most of these will have little to no impact on the current state of the game.