I had a similar problem last year. My rain sensor was activated because of a few days of heavy rain. Several days later I had a 12 hour power outage. And then it didn't water for a couple of more days. I was activating my Over Seed schedules for the first time, and for probably a different reason they wouldn't work. I ended up doing a power cycle on the Rachio to try and make all was OK. I never did figure out the rain sensor status A couple of days later I got an inch of rain and no rain sensor message, so I can only assume that it was still activated. Then three days later I got a message saying "OverSeed morning skipped since station MID_E0698 observed 1.02 in of precipitation with a total threshold of 0.5". It was really wierd that it showed up 3 days late, so probably a problem with how the PWS I used was reporting. Then everything started working fine. No rain for about a week, and then when it did rain again, I got a message that the rain sensor had been activated. (I never did get a rain sensor deactivated message during this time).
I think based on my experience that the rain sensor events probably get back to the servers, but just don't show on our logs. After my issues with it I asked if they could have the rain sensor status show somewhere on the current status, close to where it shows rain delay status. Otherwise it's not easy for us to determine the rain sensor status. Keeping my fingers crossed that they will do this in v3.0.