This morning's issue (flex supposed to run but did not) can be explained with the connectivity problem we experienced this morning (http://community.rachio.com/t/gen-2-connectivity-problem/5080/2). Regarding the moisture graph, since we were supposed to water, it is simulating watering today. This is a known issue with the moisture graph and we are determining the best way to render the data differently.
There will also be times when we determine at flex time of run (one hour before) that it doesn't need to run (very close to depletion, but not zero yet) and the forecast for the graph might predict it ran (but it really did not based on information from the morning).
I agree that the simulator needs some work in regards to today, since the truth is not always displayed how it should be, especially if you are past your watering time for the day. I'm going to have the development team look into this behavior, it might be an easy fix.