I added the zones to the daily flex schedule and the "Moisture Level" button came back but only while the schedule is enabled. The work-around I found (to track levels but not actually irrigate) was to program the start of the flex schedule a year into the future.
In my particular case, I installed Rachio in April and have experienced enough rain that I have not had to turn it on. However, I did find it extremely useful to keep track of the moisture levels as peace of mind, curiosity, and as part of calibration. If possible, please consider a formal request to bring back the persistent "Moisture Level" view even if it is not being used by the other irrigation methods. There is never harm in having data.
Actually, and perhaps this should be a separate topic, I've found that the even though the Moisture level drops to the allowed depletion, a soil moisture meter (the galvanic type) reads 80-100% moisture and my lawn shows no sign of thirsts. This is partly the reason why I haven't irrigated.
I'm shocked my soil (high clay content) holds so much water. Should I allow fuller depletion (increase allowed depletion) to better model my soil?
I'm very new to lawn care and operating under the guidance that for St. Augustin grass one should do infrequent deep irrigations, preferably only when the grass starts to show signs of thirst.