Have you tried power cycling the light? This always fixes it for me. It’s every month or so I have to do this. My Yeelights are 3 years old…
i did try it and also had a complete power outage for a few minutes. my initial thought was that the esp32 board hanged, but when i see it can connect via the xiaomi/yeelight apps i am quite sure that the problem is somewhere with home assistant.
There is an issue open here
Additional log dumps would be very helpful