I've had the same problem as well. KDP has been acting up too, I've gotten a couple of 'service unavailable errors' on there today, and nothing has updated since like 9am EST. I assume the next few days are like mini-Prime Day, with people hammering the mothership as they check out Black Friday deals.
I've already turned down all my budgets and bids in AMS, since during Prime Day I got killed by crazy overspend and really bad KENP (which make up most of my sales). I'm going to keep an eye on things, but I'm not planning on going back to my regular AMS settings till at least Saturday.