I have about 10 Cree lights and 4 motion sensors to turn them on and off. I also have Sonos speakers and a few outlets on my Smartthings network. On one day last week it seemed that communication on my network was getting bad. I’d walk into my bathroom and the light would turn on but it would not turn off in the prescribed 3 minutes of no motion.
For three days I performed factory resets on devices, rebooted the router hub, wifi router, removed and readded them to the network, removed smart apps, ran a network repair, … None of this helped. Still i’d have to press a button 3 or 4 times to get it to turn on the lights it was supposed to control.
In what I thought was an unrelated event, I noticed that my Sonos surround speakers were silent. After some poking around I found that one of my surround speakers was unplugged. I plugged it in and readded it to the Sonos network and magically my Smartthings network went back to responding to 100% of requests.
Maybe this is unrelated but the unplugged speaker was the closest device to my Smartthings hub on my network.