Like others, I found my way here looking for an answer to the “constant on” of the floodlight after dark that just recently started at my location.
Before I get to the point, a little background on the floodlight camera in question. It was ordered directly from ring in May of 2019, and was originally intalled to operate only as a floodlight sensor until I was able to get constant wifi access to its location (October 2019). The firmware shows that it is up to date, and until recently, (10 days or so) it has worked flawlessly.
In an attempt to figure out the issue, I tried the suggested fixes in this thread, as well as putting any devices that have the ring app installed into airplane mode, and yet the issue persists. What I have discovered that works 100% of the time in my situation is to remove the internet access of the floodlight, at which point the light comes on only when it senses motion, as it had done all along. The downside to this obviously is the lack of notifications, but the light does not cycle the “on->off for 5 seconds->on” routine that it recently began doing.
Suspecting someone may have been attempting remote access, I have been monitoring the inbound and outbound network traffic, and yet I can see nothing out of the ordinary.
For anyone still following the thread with the same issue, I would suggest shutting wifi off for the floodlight and see if it stops the issue, and kindly respond back.