My guess would be post stage change spikes. They always said changes going into lockdown take weeks to show up so the same should be the case coming out. It's why I've wondered about the speed we are opening up because how can they be that sure it's not going up if states are too close together to allow the stats to change?
There was a piece in the news about it yesterday quoting Imperial College about it. Their response seemed to be it's too early to tell. This brings me back to my question about the speed of opening up since that's supposed to be using data from this lot isn't it?