I’m in the process of debugging this issue myself but just wanted to know if anyone else has experience this problem. I think it may have something to do with the Smart Lighting SmartApp controls I’ve setup. While using the SmartThings app, if I inadvertently click multiple times on a StartThings Routine or a Device that is tied to multiple lights via the Smart Lighting SmartApp before it finishes, I can get the hub in a situation where the associated lights will flash on and off indefinitely until I restart the SmartThings hub. I was able to reproduce this problem on both the v1 and v2 hubs, of course I have to remove the batteries from the v2 hub to get it to reboot. If I was the only one using the app in my house, I wouldn’t be too concern. I worry if this happens while my wife uses the app and I’m not home.
It sounds to me as though you’ve set up too many automations, and two of them are fighting with each other. One turns things on, and one turns things off. That won’t work.
Maybe this is an side effect of the multiple/simultaneous? modes that some have witnessed in debugging.
or you have two smartapps on the same device as bravenel noted. IDE will identify that condition. I don’t use Smart Lighting yet, but using only one instance, I’d expect that strobing could not happen unless the modes were misbehaving in #1.
I have seen where a bulb is failing and starts to flash on and off. Nothing to do with st. Out of a lot of 10, I had 2 led bulbs that did this. Worked at first, then fails.