I have contacted support, but thought I would post here as well. Here is my email (with a couple edits):
In the past few days I've noticed pooling water along my sidewalk and grass in a few areas (and in different zones). It appears that the last zone to run will constantly leak water from the head (particularly on my low-lying two zones). For the one that I noticed was the worst, I manually ran the cycle for 1 minute and let it stop. I observed a steady stream of water coming from the lowest head (and another, but not as bad). I then unplugged the Rachio, and the flow of water stopped. This tells me that my valves are fine, and the rachio is malfunctioning. I have attached two pictures. The first of the head after letting the zone run manually and see the head is covered with water due to the flow (in a video it would be obvious). The second is after I unplugged the Rachio. The water flow has stopped (there still is a little pool of water there, but you can see the other part of the head is not covered - due to flow stopping).