Old talent leaves, new talent comes in - they could be leaving for any number of reasons, and the usual one is lack of faith in leadership. Panic is another reason.
Think about this: just because the Chief Product Officer left doesn't mean they don't have a plan. They've likely got a 2 to 5 year roadmap still. Companies like that never work from one device to another, they're always working and refining. So the rest of the product team is still there. I seriously doubt that Peter Chou is making "snap decisions" as one of the articles points out.
And it's only coming out now - the others have left over the last three months, they didn't just walk out the door in one clump. Most of them landed with competitors or companies that are adjacent to the space - that's not surprising, and it's possible they were poached for more money, more perks, more anything. If a company came to you and said, hey... let's talk about a potential position here, you'd talk, right? Talking never hurts anything, and if it turns into a sweet deal, why not take it? Once one person leaves because they found a good deal, the others might think about it, especially if they've been there for awhile.