Are you sure? The line I think you're referring to is "Two kinds of actions can provoke attacks of opportunity: moving..." but then it still elaborates that "Moving: Moving out of a threatened square usually provokes an attack of opportunity from the threatening opponent." I can see how that can be interpreted as the action prep's the AoO and the moving out of the square triggers it, but it could just as reasonably be interpreted that the Move action causes it, and then each instance of moving out of a threatened square provokes an AoO.