Update: here's the graph of rankings... anyone other suggestions for what could be causing the change? Used to steadily improve, then suddenly a change in behav

Update: here's the graph of rankings... anyone other suggestions for what could be causing the change? Used to steadily improve, then suddenly a change in behavior: http://postimg.org/image/gk0t343gp/ http://postimg.org/image/gk0t343gp/