Blue is "sent", Red is "received" and Green is "good" according to the legend for the graph. I have been seeing something similar recently, where the blue/sent is continuously at full scale, and the red/received will flatline like yours for extended periods of time. Green/good however had ups and downs.
I am in full automatic.
I wonder if this is some kind of new server control. I had noticed this behavior recently too, but didn't really give it much thought until you brought it up.
Greg H.